Ludwig Josef Johann Wittgenstein (April 26 1889 – April 29 1951) was an Austrian philosopher, best known for the Tractatus Logico-Philosophicus, the only philosophy book he published while alive. He initially focused on solving the relationships between language and the world, and believed that with TLP, he solved philosophy, and people could get on with their lives.
Later in life, though, he would end up retracting most of his statements in TLP, leading to his posthumously-published Philosophical Investigations.
His works have had profound cultural influence. Philosophical Investigations is considered one of the most important books of 20th century philosophy, and he's regularly counted amongst the greatest philosphers.
TLP inspired a Hungarian film by Péter Forgács, an album by Finnish artist M. A. Numminen, and, most relevantly to my interests, the visual novels Tsui No Sora and Subarashiki Hibi.