O. Korschelt (1853－1940) was the author of the first extensive treatise on Go in a European language (German) entitled Das Japanisch-Chinesische Spiel 'Go' published in 1880. This books has been translated into English and published as The Theory & Practice of Go.
There is disagreement as to whether Korschelt's first name was Oscar or Otto. Note: the author's name on the book says "Oscar Korschelt".
Korschelt taught the game to Edward Lasker in 1907.
Jared Beck: Yeah! That german page is really cool. I was working through this game from my copy of the book when I found this site. It's so nice to have sgf files when studying a game. I recommend the historical games on this site, especialy that game, because of the abundance of easy-to-learn-from moves.