Benedict de Spinoza's Ethics, first published in 1677, constitutes a major systematic critique of the traditional and religious foundations of philosophical thought. In it, Spinoza follows a logical step-by-step format consisting of definitions, axioms, propositions, proofs, and corollaries to create a comprehensive inquiry into the truth about God, nature, and humans' place within the universe. From these broad metaphysical themes, Spinoza derives what he considered to be the highest principles of religion and society and lays out an ethical system in which reason is the supreme value.

Though it first aroused anger and controversy rather than admiration and acceptance, A Theologico-Political Treatise was a landmark in the analysis of theology (with particular reference to the Bible and its Jewish and Christian interpretations) and its relationship to philosophy and politics. Spinoza’s scholarly analysis, based on careful study, demonstrated that the Bible was composed by many writers over the centuries - and that even the Pentateuch, the first five books, were not the work of Moses, as was generally assumed at the time.

Ethics is one of the most unique works in Western philosophy, an attempt to handle metaphysics, theology, anthropology, and ontology through the lens of geometric proofs. Spinoza felt that the path to happiness is through reason, in the use of the mind to demystify our existence and liberate us from passions and superstitions.

Perhaps one of the most revolutionary works of philosophy ever presented, The Phenomenology of Spirit is Hegel's 1807 work that is in numerous ways extraordinary. A myriad of topics are discussed, and explained in such a harmoniously complex way that the method has been termed Hegelian dialectic. Ultimately, the work as a whole is a remarkable study of the mind's growth from its direct awareness to scientific philosophy, proving to be a difficult yet highly influential and enduring work.

Aristotle's Metaphysics was the first major study of the subject of metaphysics - in other words, an inquiry into 'first philosophy', or 'wisdom'. It differs from Physics which is concerned with the natural world: things which are subject to the laws of nature, things that move and change, are measurable. In Metaphysics, the study falls on 'being qua being' - being insofar as it is being; the causes and principles of being, the causes and principles of substances.