Arguably the most important sports union figure of all time has passed away. Marvin Miller, the man behind what the MLBPA is to this day has died at 95.
One of Miller's crowning achievements (and one of the reasons he is not in the MLB Hall of Fame - yet) is that he was successful in neutering baseball's reserve clause. The following is from Michael Leeds and Peter Von Allmen's The Economics of Sports text (pp 283-284):
The Major League Baseball Players Association (MLBPA) was able to overthrow the reserve clause by outsmarting the owners rather than by suing them. Prior to 1970, all grievances by players were filed with the Commissioner, who typically sided with the owners. In the 1970 negotiations, Marvin Miller, the MLBPA's Executive Director, got the owners to agree to replace the commissioner with a three-person panel, with one member appointed by the owners, one member appointed by the union, and one member drawn from a mutually agreed upon list. The owners agreed to the commission after Miller assured them that the panel would deal only with trifling monetary matters. Then-Commissioner Bowie Kuhn would have the final say in all overarching matters that affected the integrity of the game. By couching its challenge to the reserve clause as a financial matter, the MLBPA was able to force the issue into the hands of an outside arbitrator, who ruled in favor of the players (and who was promptly dismissed by the owners).
The problem that faced players was the 1922 Federal League SCOUTUS decision that resulted in MLB's exemption from US antitrust rules. Numerous suits were brought in subsequent years challenging the reserve clause under antitrust laws, but were not upheld by the Court because of the exemption. Players in other leagues, however, successfully challenged the reserve clauses in their leagues via the court system, but MLB players were unable to do the same. So rather than using the court system, Miller outmaneuvered baseball owners in negotiations. This ultimately resulted in the Catfish Hunter decision, followed by the famous McNally-Messersmith decision.
Update: Jon Wertheim's column in Sports Illustrated today is an excellent description of what Miller meant to the players.