Perhaps the most important work of philosophy written in the twentieth century, the Tractatus Logico-Philosophicus first appeared in 1921 and was the only philosophical work that Ludwig Wittgenstein published during his lifetime. Written in short, carefully numbered paragraphs of extreme compression and brilliance, it immediately convinced many of its readers and captivated the imagination of a generation of philosophers. Influencing the Logical positivists of the 1920s and 1930s, the book later went to grip the minds of many other philosophers, convincing many that propositions were pictures of reality.