A history professor by trade, Bill O'Neal wrote five books on the high minor leagues, devoting one to each AA and AAA circuit from the 1940s/1950s. The books offer short recaps of each season with a few sidebars on interesting events and players. All are presently out of print and some are difficult to track down at reasonable prices.
- The Texas League - 1987
- The Pacific Coast League - 1990
- The American Association - 1991
- The International League - 1992
- The Southern League - 1994