Teams have different internal structures, and many of the people listed below as General Manager actually have a different title. The person listed is the individual who is the most senior person responsible for making the baseball-related decsions.
In many cases, the ballclub is owned by a corporation or a group of individuals. In that case, the individual listed as owner is the CEO, president, or managing partner.
Source: The Sporting News Baseball Guide, 1997 Edition
TEAM GENERAL MANAGER OWNER/CEO ANA Bill Bavasi Gene Autry BAL Pat Gillick Peter Angelos BOS Dan Duquette John Harrington CHW Ron Schueler Jerry Reinsdorf CLE John Hart Richard Jacobs DET Randy Smith Michael Ilitch KC Herk Robinson David Glass MIN Terry Ryan Carl Pohlad NYY Bob Watson George Steinbrenner OAK Sandy Alderson Stephen Schott/Ken Hoffman SEA Woody Woodward John Ellis TEX Doug Melvin J Thomas Schieffer TB TOR Gord Ash Paul Beeston
TEAM GENERAL MANAGER OWNER/CEO ARZ ATL John Schuerholz Ted Turner CHC Ed Lynch Andy McPhail CIN Jim Bowden Marge Schott COL Bob Gebhard Jerry McMorris FLA David Drombowski Wayne Huizenga HOU Gerry Hunsicker Drayton McLane LA Fred Claire Peter O'Malley MIL Sal Bando Bud Selig MTL Jim Beattie Claude Brochu NYM Joe McIlvaine Nelson Doubleday PHI Lee Thomas William Giles PIT Cam Bonifay Kevin McClatchy STL Walt Jocketty August Busch SD Kevin Towers John Moores SF Bob Quinn Peter Magowan