Major League Baseball Major League Baseball logo Major League Baseball (MLB) is the highest level of play in professional baseball in North America. More specifically, Major League Baseball ("MLB") refers to the entity that operates North America's two top leagues, the National League and the American League, by means of a joint organizational structure which has existed between them since 1920. Major League Baseball is governed by the Major League Constitution, an agreement that has undergone several incarnations since 1920, with the most recent revisions being made in 2001. Major League Baseball, under the direction of its Commissioner, hires and maintains the sport's umpiring crews, and negotiates marketing, labor, and television contracts. The 'closed shop' aspect of MLB effectively prevents the yearly promotion and demotion of teams into the Major League by virute of their performance (as, for example, in the English football league system, where the bottom three teams in the highest league are demoted to a lower league, and the top three from the second highest league move into the top league). MLB also maintains a unique, controlling relationship over the sport, including most aspects of minor league baseball. This is due in large part to a 1922 U.S. Supreme Court ruling which declared baseball is not considered interstate commerce (and therefore not subject to federal antitrust law), despite baseball's own references to itself as an "industry" rather than a "sport." Current Major Leagues The Major League season generally runs from early April through the end of September. Players and teams prepare for the season in spring training, primarily in Florida and Arizona, during February and March. Teams and schedule In all there are 30 teams in the two leagues: 16 in the elder National League ("NL") and 14 in the American League ("AL"). Each has its teams split into three divisions grouped generally by geography and styled "East," "Central," and "West," respectively. Each team's regular season consists of 162 games, a duration established in 1961. From 1898 to 1960, a 154-game schedule was played. Games are played predominantly against teams within each league through an unbalanced schedule which heavily favors divisional play. In 1997 Major League Baseball introduced interleague play, which was criticized by the sport's purists but has since maintained popularity with casual fans. All-Star game Early July marks the midway point of the season, during which a three day break is taken when the Major League Baseball All-Star Game is staged. The All-Star game pits players from the NL, headed up by the manager of the previous NL World Series team, against players from the AL, similarly managed, in an exhibition game. After the 2002 contest ended in a 11-innning tie because both teams were out of players, a result which proved highly unpopular with the fans, it was decided to give the game more impact on the regular season. In 2003 and 2004, the league which won the game received the benefit of home-field advantage (four of the seven games of that year's World Series taking place at their home park). It has yet to be announced if this experiment will continue past 2004. Since the 1970s, the eight position players for each team who take the field initally have been voted into the game by fans. The remaining position players, and all of the pitchers, on each league's roster are solely at the discretion of that team's manager. By MLB regulation, every team in the majors must have at least one designated all-star player, regardless of voting. This rule sometimes allows into the game players who don't necessarily "deserve" to be all-stars. Post-season At the conclusion of the regular season, the three division champions from each league, together with the non-division champion with the best regular season record ("Wild Card") qualify for post-season playoffs. The post-season currently consists of three rounds: American League Division Series and National League Division Series, each a best-of-five game series; American League Championship Series and National League Championship Series, each a best-of-seven game series played between the surviving teams from the ALDS and NLDS; and World Series, a best-of-seven game series played between the champions of each league. At the time of writing the Commissioner of Baseball, Bud Selig, has often floated the idea of international expansion and realignment of the major leagues. At the moment, however, the major leagues are each split into three divisions, and structured as follows: Current teams of Major League Baseball American League West Central East Anaheim Angels Chicago White Sox Baltimore Orioles Oakland Athletics Cleveland Indians Boston Red Sox Seattle Mariners Detroit Tigers New York Yankees Texas Rangers Kansas City Royals Tampa Bay Devil Rays   Minnesota Twins Toronto Blue Jays National League West Central East Arizona Diamondbacks Chicago Cubs Atlanta Braves Colorado Rockies Cincinnati Reds Florida Marlins Los Angeles Dodgers Houston Astros New York Mets San Diego Padres Milwaukee Brewers Philadelphia Phillies San Francisco Giants Pittsburgh Pirates Washington Nationals†   St. Louis Cardinals   † In 2002, Major League Baseball, through a subsidiary (Baseball Expos, L.P.), acquired the National League's Montreal Expos franchise with the intent of ceasing its operations. However, a new collective bargaining agreement with the powerful baseball players union in effect stopped that maneuver. The team has been relocated for 2005 to Washington D.C. and renamed the Washington Nationals. MLB continues its search for someone to acquire the franchise. Historical Major Leagues In 1969, the centennial of professional baseball, a commission chartered by Major League Baseball identified the following leagues as "major leagues". The list is sometimes disputed by baseball researchers. The MLB list included the following: 1876-present: National League of Professional Baseball Clubs 1882-1891: American Association 1884: Union Association 1890: Players League 1901-present: American League 1914-1915: Federal League Some researchers contend that the National Association (1871-1875), the Negro Leagues (primarily during the years from 1921-1946), and the first year of the American League (1900) deserve consideration as major leagues due to the caliber of player and the level of play exhibited. However, game and statistical records for these particular leagues were not kept in a consistent manner. Related articles History of baseball, for a detailed history of the Major Leagues Minor league baseball, for a list of Minor Baseball teams Negro League baseball Continental League 19th century National League teams Players, ownership, ballparks and officials Baseball Commissioners List of highest paid baseball players List of major league players with articles List of Major League Baseball principal owners List of Major League Baseball stadiums List of Major League Baseball retired numbers Statistics, milestones and records Baseball statistics: BA, ERA, etc. Baseball Hall of Fame 30-30 club and 40-40 club 300-300 club List of lifetime home run leaders through history 500 home run club List of major league players with 2,000 hits 3000 hit club 300 win club 3000 strikeout club Major League Baseball franchise post-season droughts Perfect game Unassisted triple play Triple crown Hitting for the cycle Major League Baseball titles streaks Major League Baseball titles leaders Major League Baseball attendance records Major League Baseball home run milestones List of most experienced baseball players never to play in a World Series Post-season awards Cy Young Award Rawlings Gold Glove Award Hank Aaron Award Manager of the Year Award Most Valuable Player Award The Sporting News Reliever of the Year Award (prior to 2001, TSN Fireman of the Year) Rolaids Relief Man of the Year Award Rookie of the Year Award Silver Sluggers Exhibition and playoffs All-Star Game National League pennant winners 1876-1900 American League pennant winners 1901-68 National League pennant winners 1901-68 MLB division winners (since 1969) American League Division Series (ALDS) National League Division Series (NLDS) American League Championship Series (ALCS) National League Championship Series (NLCS) World Series Other Information List of regular season MLB games played at alternate parks External links Official MLB website Baseball-reference.com: a comprehensive, intra-hyperlinked statistical encyclopedia Baseball Prospectus Baseball Think Factory All-Baseball.com The Hardball Times ESPN.com - Baseball Index FAVORITE ARTICLES: History of the World    History of the United States    History of Europe    Ancient History    History    Military History    World War I    Bombing of Dresden    California    US Constitution    Frank Sinatra    Boston    Marbury v. 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