Philosophers have long puzzled over the nature of space, time, and matter. These inquiries led to the flowering of physics with the Scientific Revolution in the 17th century. Since then, the spectacular success of modern physics might appear to have made philosophy irrelevant. But new theories have created a new range of philosophical concerns: What is the shape of space? Is time travel possible? Is there a grand unified theory that unites all of physics?

As recently as 1990, it seemed plausible that the solar system was a unique phenomenon in our galaxy. Thanks to advances in technology and clever new uses of existing data, now we know that planetary systems and possibly even a new Earth can be found throughout galaxies near and far.

Imagine a region in space where the force of gravity is so strong that nothing - not even light - can escape. This phenomenon is a black hole: one of the most exotic, mind-boggling, and profound subjects in astrophysics. Nearly everyone has heard of black holes, but few people outside of complex scientific fields understand their true nature and their implications for our universe. No movie, novel, or other fictional treatment of black holes matches Professor Filippenko’s absorbing presentation of the actual science behind these amazing objects.

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.

"It doesn't take an Einstein to understand modern physics," says Professor Wolfson at the outset of these 24 lectures on what may be the most important subjects in the universe: relativity and quantum physics. Both have reputations for complexity. But the basic ideas behind them are, in fact, simple and comprehensible by anyone. These dynamic and illuminating lectures begin with a brief overview of theories of physical reality starting with Aristotle and culminating in Newtonian or "classical" physics.

In this 24-lesson course aimed at non-scientists, noted particle physicist Dr. Don Lincoln of Fermi National Accelerator Laboratory covers more than a century of progress in physics, describing exactly how scientists reach the conclusions they do. He starts with the atom, which was long hypothesized but wasn’t definitively proven until a paper by Albert Einstein in 1905. That was just the beginning, as researchers probed ever deeper into the atom’s complex structure, leading to the weird findings of quantum mechanics.

Between 1861 and 1865, the clash of the greatest armies the Western hemisphere had ever seen turned small towns, little-known streams, and obscure meadows in the American countryside into names we will always remember. In those great battles, those streams ran red with blood-and the United States was truly born.

Look beyond the abstract dates and figures, kings and queens, and battles and wars that make up so many historical accounts. Over the course of 48 richly detailed lectures, Professor Garland covers the breadth and depth of human history from the perspective of the so-called ordinary people, from its earliest beginnings through the Middle Ages.

Nothing has had a more profound impact on the development of modern civilization than thermodynamics. Thermodynamic processes are at the heart of everything that involves heat, energy, and work, making an understanding of the subject indispensable for careers in engineering, physical science, biology, meteorology, and even nutrition and culinary arts. Get an in-depth tour of this vital and fascinating science in 24 enthralling lectures suitable for everyone from science novices to experts who wish to review elementary concepts and formulas.

The Science of Information: From Language to Black Holes covers the exciting concepts, history, and applications of information theory in 24 challenging and eye-opening half-hour lectures taught by Professor Benjamin Schumacher of Kenyon College. A prominent physicist and award-winning educator at one of the nation’s top liberal arts colleges, Professor Schumacher is also a pioneer in the field of quantum information, which is the latest exciting development in this dynamic scientific field.

England: From the Fall of Rome to the Norman Conquest takes you through the mists of time to the rugged landscape of the British Isles. Over the course of 24 sweeping lectures, Professor Jennifer Paxton of The Catholic University of America surveys the forging of a great nation from a series of warring kingdoms and migrating peoples. From Germanic tribes to Viking invasions to Irish missionaries, she brings to life an underexamined time and place.

Consider these commonly held scientific beliefs: Planetary orbits are fixed ellipses; we only use 10 percent of our brains; nothing travels faster than light; a thrown object’s trajectory is a parabola. They seem correct, but they’re all misconceptions that aren’t entirely accurate. There’s much more to the story than you think. These magnificent 24 lectures are devoted to busting myths, clearing up confusion, and giving you scientific epiphanies that could change how you think about your everyday world.

Guiding you chronologically through the life and times of this master statesman, Professor Shelden takes you from the dawn of Churchill’s political career to his final years in a much-changed geopolitical landscape. You’ll examine Churchill’s beginnings as a young liberal statesman, his rise to the Admiralty and his relentless push for an imposing naval force, his fight against the Nazis, his equally dramatic postwar career suspended between two different cold wars (against the Soviets and Britain’s Labour party), and more.

Locked inside the DNA of every species that ever lived are endless stories - about origins, ancestors, fate, and much more. Until recently, these secrets were completely inaccessible. But with the help of new technologies, scientists are now reading the hidden history of DNA, making remarkable discoveries about ourselves and our fellow species. Your gateway to this treasure trove of information is Unlocking the Hidden History of DNA, 12 informative and accessible lectures delivered by New York Times best-selling author Sam Kean.

Trace the growth of communism from Stalin’s consolidation of power to the establishment of communist regimes in Eastern Europe, China, Korea, Vietnam, and elsewhere in Communism in Power: From Stalin to Mao. These 12 half-hour lessons shed intriguing light on a revolutionary movement that played an outsized role in the 20th century and continues to shape 21st-century geopolitics.

In The Black Death: New Lessons from Recent Research, celebrated medievalist Dorsey Armstrong shares the fascinating new story of this old pandemic—revealed by dedicated researchers working with 21st-century technologies and a knowledge of language and history that now provide input from all geographic areas of the medieval world. In seven engaging lectures, Professor Armstrong corrects explanations of the pandemic that are now known to be inaccurate and offers a more robust description of plague biology than has ever been known.

From the days of Freud and Skinner to the modern science of fMRIs and genetics, Introduction to Psychology is a grand introduction to one of the most captivating fields of inquiry - where the subject is you, and everyone around you. Taught by Professor Catherine A. Sanderson of Amherst College, these 36 insightful lessons not only give you a panoramic grounding in the history, methods, and fundamental findings of psychology, but they also introduce you to the most up-to-date 21st-century research and discoveries.

Creation stories, found within many ancient cultures, are traditional accounts of the origins of the universe, the earth, and humanity. Often embodied as epic poetry, and told through the acts of divine beings, creation stories illuminate the values, beliefs, and creeds of the earliest civilizations. As such, these stories show us how early cultures made sense of the human condition, in theological, philosophical, and political terms. These 12 dynamic and thought-provoking lectures offer you a penetrating look at the origin stories of the great civilizations of the Mediterranean.

Epigenetics is the science of living DNA, charting the chemical pathways that spur DNA into action by turning genes on and off. While the Human Genome Project of the early 2000s was hailed as the key to understanding human heredity and disease, that historic effort was just the beginning. It has taken epigenetics to fill in the picture, explaining how the fixed code of our genome is implemented in countless living processes.

Trace the growth of communism from Stalin’s consolidation of power to the establishment of communist regimes in Eastern Europe, China, Korea, Vietnam, and elsewhere in Communism in Power: From Stalin to Mao. These 12 half-hour lessons shed intriguing light on a revolutionary movement that played an outsized role in the 20th century and continues to shape 21st-century geopolitics.

As recently as 1990, it seemed plausible that the solar system was a unique phenomenon in our galaxy. Thanks to advances in technology and clever new uses of existing data, now we know that planetary systems and possibly even a new Earth can be found throughout galaxies near and far.

Hannibal Barca is famous for marching an eclectic mix of troops across the Alps and into the Roman heartland during the Second Punic War. But how much do we know about the world Hannibal was born into and came of age in? In Hannibal: The Military Genius Who Almost Conquered Rome, get to know one of history’s most impressive generals from the political and military conflicts that defined his adolescence to the battles that made him famous. These 15 lectures will paint a portrait of not only Hannibal, but also his enemies and allies.

Great minds have long sought to understand the relationship between music and mathematics. Both involve patterns, structures, and relationships. Both generate ideas of great beauty and elegance. Music is a fertile testing ground for mathematical principles, while mathematics explains the sounds instruments make and how composers put those sounds together. Understanding the connections between music and mathematics helps you appreciate both, even if you have no special ability in either field....

How did communism become such a pervasive economic and political philosophy? Why did it first take root in early 20th-century Russia? These and other questions are part of a fascinating story whose drama has few equals in terms of sheer scale, scope, or human suffering and belief. These 12 lectures invite you to go inside communism’s journey from a collection of political and economic theories to a revolutionary movement that rocked the world.

In The Vietnam War, you will learn about the causes and consequences of the war in Vietnam. You will explore the scope of American intervention from air campaigns to large-scale military operations on the ground. You will survey the history of Vietnam from colonial Indochina onward, getting to know the homegrown ideas, personalities, and politics that would come to shape the conflict. You will reconstruct major military operations like the Tet Offensive and Rolling Thunder.

Have you ever been in love? Falling in love is the easiest thing in the world. The difficult part comes later, when you are trying to stay in love. Half of all marriages in the United States end in divorce. As it turns out, failing in love is just as easy as falling in love.

Gravity controls everything from the falling of an apple to the rising of ocean’s tides to the motions of the heavens above. If you’ve ever wondered how this most puzzling force works across our entire universe, you will be delighted by this 24-part course that is accessible to any curious person, regardless of your science education. No other product on the market presents the subject of gravity in as much detail as this course, which will follow the past 400 years of research and experimentation in the field.

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.

Imagine a world without bees, butterflies, and flowering plants. That was Earth 125 million years ago. Turn back the clock 400 million years, and there were no trees. At 450 million years in the past, even the earliest insects had not yet developed. And looking back 500 million years, the land was devoid of life, which at that time flourished in a profusion of strange forms in the oceans. These and other major turning points are the amazing story of evolution.

World War II is one of the most harrowing and impactful events in human history. Our imaginations may be captured by the sweeping military battles, but the story of war is the story of humans, everyday people trying to do their bit in a world falling apart around them.