Wikipedia
Retrosheet is a non-profit organization whose website features major league baseball box scores and play-by-play narratives for almost every contest from 1871–1872, 1874, 1911 National League, and since 1913. It also includes scores from every Major League Baseball game played since the 1871 season (what is officially the inception of Major League Baseball history), as well as all All-Star, League Championship Series and World Series games.
Retrosheet was founded in 1989 by Dr. David Smith, a biology professor at the University of Delaware. Building on momentum begun by writer Bill James' Project Scoresheet in 1984, Smith brought together a host of like-minded individuals to compile an accessible database of statistical information previously unavailable to the general public.
Smith originally contacted teams and sportswriters in order to gain access to their scorebooks, while other contributors researched old newspapers for play-by-play accounts. Marshalling the computer expertise of a number of these people, Smith used these accounts to build a wealth of new data. The result has allowed fans and historians to explore new aspects of baseball history by using pertinent information.
While all teams eventually contributed to the project, gaps occurred with some teams, most notably the Atlanta Braves, Houston Astros and Pittsburgh Pirates of the late 1960s. The Braves, Pirates and Cincinnati Reds have also been lacking information from previous eras.
Surprisingly, the first 40 years of the 20th century have uncovered more play-by-play coverage than the period of the 1940s. The lack of television (and prior to that, radio) accounts serve as the main reasons for this disparity, while World War II limited the space that had been used for such information.
In 1994, the organization began sending out a quarterly newsletter to interested parties, then added a website in 1996. Following publication of the January 2002 newsletter, the organization chose to end sending out the paper version. Instead, they added periodic updates via the website.
Retrosheet's Board of Directors meets each year in conjunction with the Society for American Baseball Research's annual convention. Many of Retrosheet's contributors are SABR members.