The General manager is the executive largely in charge of making personnel decisions for a team, such as signing free agents, making trades and negotiating contracts. He is also the person who sets out the team's "vision" of how and when it will seek to compete, its strategy regarding the amateur draft, etc. He is responsible for hiring the team's manager and a good working relationship between the two is essential, although some teams have thrived on creative tensions between the two top officials. In addition to the manager, the GM oversees the work of the scouting director and the rest of the scouting department and of player development (i.e. the farm system). There have been situations, however, where the manager held the real power and the GM was there to execute the strategies decided at his level. Typically, the GM reports to the team President and he may himself hold the title of Vice-President. His actual title will vary from organization to organization, but the position exists within every team.
The position began to emerge as a separate function in the 1930s and was not used throughout Major League Baseball until the 1960s (teams like the Philadelphia Athletics and the original Washington Senators continued to operate on a "family-owned business" model for decades after others had moved to a more modern management style.
For a long time, most General managers were former players, as the job was seen as a natural progression from that of manager. There were also a number of owners and other senior executives who were their own General managers (Bill Veeck and Horace Stoneham for example), but that is no longer the case. Today's General Manager tends to have a sports business background and be relatively young (the Ivy League-educated Theo Epstein, who got the Boston Red Sox over the World Series hump, is the prototype of the new style of GM). As a result, today's General Managers tend to be less flashy than their predecessors, but to have a much greater grasp of finances and sabermetrics.
- Mark L. Armour and Daniel R. Levitt: Paths to Glory: How Great Baseball Teams Got That Way, Potomac Books , Dulles, VA, 2003. ISBN 978-1574885606
- Mark L. Armour and Daniel R. Levitt: In Pursuit of Pennants: Baseball Operations from Deadball to Moneyball, University of Nebraska Press, Lincoln, NE, 2015. ISBN 978-0-8032-3497-0
- Buzzie Bavasi with John Strege: Off the Record, Contemporary Books, Chicago, IL, 1987. 
- Buzzie Bavasi with Jack Olsen: "The Real Secret of Trading", Sports Illustrated, June 5, 1967, p. 47. 
- Thomas Boswell: "Trader Jack, Whitey the Rat and Other Good Ideas", in Why Time Begins on Opening Day, Penguin Books, New York, 1984, pp. 61-76.
- Michael Lewis: Moneyball: The Art of Winning an Unfair Game, W. W. Norton & Company, New York, NY, 2003. ISBN 978-0393057652
- Bob Nightengale: "GM role not what it used to be", USA Today Sports, November 11, 2015.