Many Americans remember a family road trip to visit one of our 63 national parks. Why did Americans start preserving these sites of natural and historic interest? How were these parks selected, and what steps did conservationists, activists, philanthropists, politicians, and others take to protect millions of acres against the booming developments of an expanding nation? An award-winning writer, researcher, and American Studies scholar, Dr. Megan Kate Nelson tackles these questions as she takes you on a marvelous journey through some of the most beautiful places on Earth.

From the 17th to 18th centuries, bold thinkers cast off the authority of ancient traditions and embraced reason as the primary tool for understanding the world. These rationalists, or early modern philosophers, included René Descartes, Baruch Spinoza, and Gottfried Wilhelm Leibniz—visionaries whose answers to profound questions remain relevant today. Early Modern Philosophy: Descartes and the Rationalists covers the key philosophers of this period in 12 fascinating half-hour lectures, presented by award-winning teacher James D. Reid, Professor of Philosophy at Metropolitan State University.

Whether you’re buying a home, saving for retirement, running a business, or just plain speculating, it’s important to understand financial markets. These are the engines of commerce in today’s world, powering economic activity and steering the flow of capital. Taught by Professor Connel Fullenkamp of Duke University, Understanding the World of Financial Markets is aimed at the ordinary investor and surveys the impressive range of financial markets—from stocks and bonds to futures, options, real estate, private equity, and virtual assets.

Accompanied by a selection of guests, Professor Jortner takes you through a mind-bending exploration of the history that could have been. Captivating storytellers and imaginative thinkers, these experts show how history is contingent on split-second decisions, near misses, and sheer dumb luck. By reflecting on what didn’t happen, 10 Great What-Ifs of American History gives you new insights on what did happen—and the impact on our world today.

In the 12 fascinating lectures of Gut Health Explained, Dr. Gabrielle Fundaro shares the latest scientific knowledge about the trillions of organisms that live in your gut. In this course, you'll learn how to navigate the evolving landscape of gut microbiome science while gaining a deep understanding of the intricate interplay between you and your microbiome.

We’re living in a golden age of scientific breakthroughs and technological advancements. Now, you have the chance to dig into some of the most fascinating and important scientific advancements in recent years. Unexpected, consequential, and often counterintuitive, 12 Revolutionary Discoveries That Could Change Everything offers an inspiring introduction to science in the 21st century. Taught by Scientific American editor in chief Laura Helmuth, these eye-opening lectures will satiate even the most inquisitive mind.

What is it about Stoicism that Marcus found so important then, and that millions find relevant today? In the 12 fascinating lectures of Books That Matter: Meditations, professor Massimo Pigliucci explores the questions Marcus believed were crucial to address in a life of value, the answers he proposed, and the many ways in which you can use Stoic philosophy. While Meditations was originally written for an audience of just one, what Marcus wanted to examine certainly still applies to us today. What exactly should we be mindful of in this life?

In Communism in Decline: From Sputnik to Gorbachev, Professor Vejas Gabriel Liulevicius reveals the internal and external forces that ripped apart the grand communist experiment. What were the mistakes made by the Soviet leaders who believed too deeply in their own propaganda? And why were they not able to see the many ironies in their own poor decisions? In 12 fascinating lectures, you will learn how the Soviet Union went from winning the space race against the United States in 1957 to Gorbachev’s resignation and the dissolution of the great experiment in 1991.

In London in the Time of Dickens, you’ll get the unique opportunity to experience the British capital through the eyes of a literary master whose work is inextricably tied to the city and its rich history. Throughout 12 lectures taught by Professor Lillian Nayder of Bates College, you’ll tour the city of London in a time of rapid transformation through the life and work of Charles Dickens, uncovering the history of the metropolis, while also witnessing the everyday experiences of Londoners from all walks of life as Dickens represents them.

The 30 years of contemporary US history following the fall of the Soviet Union tend to get short shrift, perhaps because this period of history is still being written, or perhaps because the end of the Cold War is a natural stopping point, an inflection point when one story ends and something new - something unpredictable - begins. Nonetheless, events of today have been profoundly shaped by the past several decades, and one must understand this recent history to understand the world today.

America was made by the railroads. The opening of the Baltimore & Ohio line—the first American railroad—in the 1830s sparked a national revolution in the way that people lived thanks to the speed and convenience of train travel. Built through heroic effort, the American railroad network was bigger in every sense than Europe's, and facilitated everything from long-distance travel to commuting and transporting goods to waging war. It united far-flung parts of the country, boosted economic development, and was the catalyst for America's rise to world-power status.

Game theory is the study of strategic decision-making in politics, sports, diplomacy, and a host of other areas, but especially in economics, where game theory flourishes. Understanding Economics: Game Theory introduces you to this fascinating field, which combines the fun and challenge of games with the logic of brain teasers. In 12 engaging half-hour lessons, Professor Jay R. Corrigan of Kenyon College analyzes such classic games as the prisoner’s dilemma and the hawk-dove game.

Sex. The word makes some people giggle or blush, while others may draw back in discomfort. So, why do we find it so difficult to talk openly about sex? Much of our reticence in discussing and acknowledging the realities of sex comes, at least in part, from a unique time and place: medieval Europe. In the 12 episodes of Sex in the Middle Ages, Professor Jennifer McNabb and a panel of experts in medieval history and literature will take you back to the period between the fall of Rome and the rise of the Renaissance to explore the ideals and realities of sex and sexuality.

The Vikings evoke striking images of horned helmets, battle axes, and merciless coastal raids. Remembered for their shocking brutality and impressive naval prowess, these marauding pirates from the North have inspired poetry, fantasy novels, plays, symphonies, and even comic book heroes over the last 12 centuries. But do any of these enduring tropes reflect reality? Who were the Vikings really? What do we know about the period that bears their name? Explore these questions and more in The Viking Age, a 12-lecture course that corrects the record on a transformative period in world history.

Many Americans know that our nation’s founders drew inspiration from the political systems of ancient Rome and Greece. But what exactly were these influences? And did they shape the United States in far-reaching ways? In these 24 compelling lectures, Professor Winterer takes you on a journey into the thought and actions of the American revolutionaries, showing how classical antiquity shaped every aspect of the revolutionary and founding era.

We are in the midst of a global mental health crisis, and mental illnesses are on the rise. But what causes mental illness? And why are mental health problems so hard to treat? Drawing on decades of research, Harvard psychiatrist Dr. Chris Palmer outlines a revolutionary new understanding that for the first time unites our existing knowledge about mental illness within a single framework: mental disorders are metabolic disorders of the brain. Brain Energy will transform the field of mental health, and the lives of countless people around the world.

How the Earth Works takes you on an astonishing journey through time and space. In 48 lectures, you will look at what went into making our planet - from the big bang, to the formation of the solar system, to the subsequent evolution of Earth.

Richard Dawkins' brilliant reformulation of the theory of natural selection has the rare distinction of having provoked as much excitement and interest outside the scientific community as within it. His theories have helped change the whole nature of the study of social biology, and have forced thousands to rethink their beliefs about life.

Hilarious, fascinating, and a roller coaster of dizzying, historical what-ifs, Napoleon's Hemorrhoids is a potpourri for serious historians and casual history buffs. In one of Phil Mason's many revelations, you'll learn that Communist jets were two minutes away from opening fire on American planes during the Cuban missile crisis, when they had to turn back as they were running out of fuel. You'll discover that before the Battle of Waterloo, Napoleon's painful hemorrhoids prevented him from mounting his horse to survey the battlefield.

Chemistry and Our Universe: How It All Works is your in-depth introduction to this vital field, taught through 60 engaging half-hour lectures that are suitable for any background or none at all. Covering a year’s worth of introductory general chemistry at the college level, plus intriguing topics that are rarely discussed in the classroom, this amazingly comprehensive course requires nothing more advanced than high-school math. Your guide is Professor Ron B. Davis, Jr., a research chemist and award-winning teacher at Georgetown University.

Astrophysicist Neil deGrasse Tyson has attracted one of the world’s largest online followings with his fascinating, widely accessible insights into science and our universe. Now, Tyson invites us to go behind the scenes of his public fame by unveiling his candid correspondence with people across the globe who have sought him out in search of answers. In this hand-picked collection of 100 letters, Tyson draws upon cosmic perspectives to address a vast array of questions about science, faith, philosophy, life, and of course, Pluto.

Aubrey Clayton traces the history of how statistics went astray, beginning with the groundbreaking work of the 17th-century mathematician Jacob Bernoulli and winding through gambling, astronomy, and genetics. Clayton recounts the feuds among rival schools of statistics, exploring the surprisingly human problems that gave rise to the discipline and the all-too-human shortcomings that derailed it.

Welcome to the Universe is a personal guided tour of the cosmos by three of today's leading astrophysicists. Inspired by the enormously popular introductory astronomy course that Neil deGrasse Tyson, Michael A. Strauss, and J. Richard Gott taught together at Princeton, this book covers it all - from planets, stars, and galaxies to black holes, wormholes, and time travel.

In this illuminating audiobook, Tyson and coauthor James Trefil, a renowned physicist and science popularizer, take on the big questions that humanity has been posing for millennia - How did life begin? What is our place in the universe? Are we alone? - and provide answers based on the most current data, observations, and theories.

The real stories behind the scenery of America’s national parks. For 12 years, Andrea Lankford lived in the biggest, most impressive national parks in the world, working a job she loved. She chaperoned baby sea turtles on their journey to sea. She pursued bad guys on her galloping patrol horse. She jumped into rescue helicopters bound for the heart of the Grand Canyon. She won arguments with bears. She slept with a few too many rattlesnakes. Hell yeah, it was the best job in the world! Fortunately, Andrea survived it.

America was made by the railroads. The opening of the Baltimore & Ohio line—the first American railroad—in the 1830s sparked a national revolution in the way that people lived thanks to the speed and convenience of train travel. Built through heroic effort, the American railroad network was bigger in every sense than Europe's, and facilitated everything from long-distance travel to commuting and transporting goods to waging war. It united far-flung parts of the country, boosted economic development, and was the catalyst for America's rise to world-power status.

Accompanied by a selection of guests, Professor Jortner takes you through a mind-bending exploration of the history that could have been. Captivating storytellers and imaginative thinkers, these experts show how history is contingent on split-second decisions, near misses, and sheer dumb luck. By reflecting on what didn’t happen, 10 Great What-Ifs of American History gives you new insights on what did happen—and the impact on our world today.

In London in the Time of Dickens, you’ll get the unique opportunity to experience the British capital through the eyes of a literary master whose work is inextricably tied to the city and its rich history. Throughout 12 lectures taught by Professor Lillian Nayder of Bates College, you’ll tour the city of London in a time of rapid transformation through the life and work of Charles Dickens, uncovering the history of the metropolis, while also witnessing the everyday experiences of Londoners from all walks of life as Dickens represents them.

The 24 revealing lectures of Unsung Heroes of the Ancient World reconstruct over a dozen biographies from the classical world—most of them little-known, some of them quite unlikely heroes. With Professor Emeritus Gregory Aldrete as your expert guide, you will meet the ambitious travel writers, dedicated engineers, careful cartographers, diligent farmers, woman philosophers, devoted wives, skilled military generals, African rebels, Persian kings, and impressive athletes who stood out among their peers centuries ago.

Right this minute, your body is carrying roughly 38 trillion microbial cells along with it—and in the vast majority of cases, you couldn’t live without them. On top of that, you harbor around 380 trillion viruses, most of which are either beneficial or benign. The Hidden Power of Microbes draws back the curtain on this vast microworld in 24 half-hour lectures delivered by acclaimed science communicator Dr. Melissa Booth, research scientist, professor, and Founder and Principal of The Science Communicator, devoted to training scientists to tell accurate, compelling stories about their fields.

In the 12 fascinating and action-oriented lectures of Treating Anxiety, Dr. Ellen Hendriksen describes the causes and symptoms of numerous anxiety disorders—from generalized anxiety disorder to social anxiety to panic. In her calming manner, and always backed by rigorous scientific studies, she will give you numerous tools and exercises you can employ immediately to help treat your own anxiety. After all, few of us are in danger of being eaten by a bear these days and, as Dr. Henricksen points out, we don’t want to spend our lives hiding in the metaphorical cave.

For millennia, philosophers and scientists have been trying to unlock the secrets of the mind with only limited success—until now. Today, with modern technologies including the best in neuroscience, medical imaging, and recent advances in artificial intelligence, we are making more progress than ever before. In Introduction to Cognitive Science, Professor Thad A. Polk takes you on a fascinating tour of the latest discoveries in the relatively new field of cognitive science. In 24 exciting lectures, Professor Polk shares dozens of the most challenging questions in cognitive science today.

The promise of America is that the country is based on an idea, one where everyone is created equal and equally free to chart their own course. From 13 newly independent states ratifying a national constitution to the heated debates in the halls of Congress today, American politics is about negotiation over what our country is—and where we are going.

Thought experiments are “what if” scenarios that invite us to look carefully at how we think and view the world. They’ve been used throughout history by philosophers and other thinkers to explore our intuitions and ways of reasoning, to find solutions to problems, and to expand our knowledge of ourselves and the world. In these 24 eye-opening lectures, Professor Breyer takes you deeply into the historical tradition of thought experiments, shining a light on both the purpose and the outcomes of these compelling mental voyages.

Many Americans remember a family road trip to visit one of our 63 national parks. Why did Americans start preserving these sites of natural and historic interest? How were these parks selected, and what steps did conservationists, activists, philanthropists, politicians, and others take to protect millions of acres against the booming developments of an expanding nation? An award-winning writer, researcher, and American Studies scholar, Dr. Megan Kate Nelson tackles these questions as she takes you on a marvelous journey through some of the most beautiful places on Earth.

The history of the Constitution is therefore a history of ideas that define our country and our national identity—and it’s a fascinating and revealing story. The US Constitution Through History gives you the opportunity to explore the story of this powerful document, as well as the way our interpretation of it has evolved. In 24 riveting lectures, Professor Eric Berger of the University of Nebraska takes you on a journey through America’s constitutional history. He takes you inside the minds of the Framers and unpacks the ideas that led to the break from England.

The Victorian Internet tells the colorful story of the telegraph's creation and remarkable impact and of the visionaries, oddballs, and eccentrics who pioneered it, from eighteenth-century French scientist Jean-Antoine Nollet to Samuel F. B. Morse and Thomas Edison. The electric telegraph nullified distance and shrank the world quicker and further than ever before or since, and its story mirrors and predicts that of the Internet in numerous ways.

Religion is foundational to what it means to be human. Our quest for meaning is as ancient as our very existence, stretching back to a time when Neanderthal burials and Paleolithic figurines suggest our ancestors recognized a power that transcended visible reality. From ancient civilizations to the 21st century, belief in a higher power seems to be a universal human instinct. These 12 thought-provoking lectures introduce you to the world of comparative religion, giving you insights into a variety of religious expressions and human cultures.

Now, you can learn the remarkable stories surrounding monumental inventions - and how consequential these inventions were to history. Taught by Professor W. Bernard Carlson of the University of Virginia, who is an expert on the role of innovation in history, these 36 enlightening lectures give you a broad survey of material history, from the ancient pottery wheel to the Internet and social media. Along with recounting the famous inventions you might expect, this course explores a number of surprising innovations, including beer, pagodas, and the operating room.

From the 17th to 18th centuries, bold thinkers cast off the authority of ancient traditions and embraced reason as the primary tool for understanding the world. These rationalists, or early modern philosophers, included René Descartes, Baruch Spinoza, and Gottfried Wilhelm Leibniz—visionaries whose answers to profound questions remain relevant today. Early Modern Philosophy: Descartes and the Rationalists covers the key philosophers of this period in 12 fascinating half-hour lectures, presented by award-winning teacher James D. Reid, Professor of Philosophy at Metropolitan State University.