Here is the essential guide to philosophy, an authoritative yet fun reference book and timeline on the compilation of human knowledge. Both art and science attempt answers to the big questions-what is truth, how to be good, and where did we come from?-but philosophy is the interpreter we turn to verify it all. We need it to make sense of the simplest math and the most esoteric of poetry and it has even created a science of information itself. We begin our journey at the boundary of myth and reason and along the way we visit the thoughts of the most high-flying of minds, Socrates, Descartes, Kant and others, who could see that nothing, not ever-changing words, limitless numbers or mystical visions, were beyond examination. And we shall see that philosophy, far from being the work of dead geniuses, is today at the heart of our battle to make sense of the quantum Universe.