Through the 2008 season, that is Hall of Famer Tom Seaver who had 25 wins in 1969.
Jack Chesbro with 41 for the 1904 team.
That would be John Coleman of the 1883 Philadelphia Quakers who lost 48 games (w/l record was 12-48). Since 1900, the most losses in a season by a pitcher is 29 by Hall of Famer Vic Willis of the...
Cy Young - http://www.baseball-reference.com/y/youngcy01.shtml
Nolan Ryan