A book by Will Durant that profiles several prominent Western philosophers and their ideas, from Socrates and Plato to Friedrich Nietzsche. Durant attempts to show the interconnectedness of their ideas and how one philosopher's ideas inspired those who came after him. The book consists of eleven chapters, with the first nine focusing on a single philosopher each, while the last two chapters provide brief profiles of three philosophers from the early twentieth century. The book was published in 1924, and a second, revised edition appeared in 1933. It was originally published as a set of booklets in the Little Blue series of inexpensive handbooks for the working man. It proved so popular that it was compiled and published in hardcover by Simon & Schuster in 1926.