For some of the worldas great thinkers, including Aristotle, Aquinas, and Hegel, philosophy is a vast system of fixed, capital-T Truth for humankind to discover, explore and comprehend. For others, even among those with philosophies as diverse as William James and Ludwig Wittgenstein, philosophy is simply a tool, or a process for ascertaining individual factual truths specific to a given time and place. It is often said that if you ask any ten philosophers to define their subject, youare likely to get ten different answers. Here, presented for non-specialist readers, is an easy-to-understand survey of ideas put forth by 100 important philosophers, from the pre-Socratics of ancient Greece to the analytic philosophers of the present day. Each thinker is summarized in a single illustrated page, or in many instances, in a two-page spread. Each entry includes the philosopheras birth and death dates, titles of major works, major influences, a capsule biographical sketch, and a brief summary