Originally started in 1995, the Stanford Encyclopedia of Philosophy (SEP) has provided students, educators, and the general public with a dynamic trove of information for over two decades. Each fascinating entry is verified and maintained by subject editors, providing an authoritative reference work at no cost to its readers. Consider this entry on Ludwig Wittgenstein, deemed by many to be the greatest philosopher of the 20th century. Wittgenstein was born in Vienna in 1889 into a wealthy family of industrialists. After giving away his wealth, the intransigent and itinerant young man joined the Austrian Army, was captured and held as a prisoner of war, and, in the midst of it all, penned his Tractatus Logico-Philosophicus. Here readers may peruse a short account of Wittgenstein's troubled life and then delve into his philosophy, which has been conveniently divided into early and late periods. Readers will also find Academic Tools that may help with questions about how to cite the SEP, Other Internet Resources about Wittgenstein, and Related Entries from the SEP's bountiful archives. Lovers of modern philosophy will find much to enjoy on this reliable and nuanced treatment of one of the greats.