Major League Baseball (MLB) is a professional baseball organization that is the oldest of the four major professional sports leagues in the United States and Canada, in fact the oldest professional sports league in the world.
A total of 30 teams now play in the American League (AL) and National League (NL), with 15 teams in each league.
The AL and NL operated as separate legal entities from 1901 and 1876 respectively.
After cooperating but remaining legally separate entities since 1903, in 2000 the leagues merged into a single organization led by the Commissioner of Baseball.
The organization also oversees minor league baseball leagues, which comprise about 240 teams affiliated with the major-league clubs.
With the World Baseball Softball Confederation, MLB manages the international World Baseball Classic tournament.

Baseball's first professional team was founded in Cincinnati in 1869.
The first few decades of professional baseball were characterized by rivalries between leagues and by players who often jumped from one team or league to another.
The period before 1920 in baseball was known as the dead-ball era; players rarely hit home runs during this time.
Baseball survived a conspiracy to fix the 1919 World Series, which came to be known as the Black Sox Scandal.
The sport rose in popularity in the 1920s, and survived potential downturns during the Great Depression and World War II.
Shortly after the war, baseball's color barrier was broken by Jackie Robinson.

New York City is for many sports fans synonymous with the New York Yankees and their logo.
The team is noted as having been the team of many of the all-time greats in the history of the game, and for having won more titles than any other US major professional sports franchise.
The city was also host to two other highly popular baseball teams in the National League, the Brooklyn Dodgers and the New York Giants, before their transfer to California beginning with the 1958 season.
The Yankees' chief rivals, the Boston Red Sox, also enjoy a huge following in Boston and throughout New England.
The fierce National League rivalry between the former Brooklyn Dodgers and New York Giants was transferred to the West Coast when the teams became the Los Angeles Dodgers and the San Francisco Giants, and California has always been among the US states which have supplied the most players in the major leagues.
Philadelphia sports fans have rooted for the Phillies since 1883, as they are the oldest continuous, one-name, one-city franchise in all of professional American sports.
Philadelphia Phillies fans are known for their rabid support of their team throughout Philadelphia and the Delaware Valley, and have famously been dubbed as the "Meanest Fans in America".
 Chicago sports fans also avidly follow the Chicago Cubs and the Chicago White Sox despite the comparative lack of success for the teams over their histories.

The 1950s and 1960s were a time of expansion for the AL and NL, then new stadiums and artificial turf surfaces began to change the game in the 1970s and 1980s.
Home runs dominated the game during the 1990s, and media reports began to discuss the use of anabolic steroids among Major League players in the mid-2000s.
In 2006, an investigation produced the Mitchell Report, which implicated many players in the use of performance-enhancing substances, including at least one player from each team.

Today, MLB is composed of thirty teams: twenty-nine in the United States and one in Canada.
Teams play 162 games each season and five teams in each league advance to a four-round postseason tournament that culminates in the World Series, a best-of-seven championship series between the two league champions that dates to 1903.
Baseball broadcasts are aired throughout North America and in several other countries throughout the world.
Games are aired on television, radio, and the Internet.
MLB has the highest season attendance of any sports league in the world with more than 74 million spectators in 2013.
Major League Baseball (MLB) is a professional baseball organization that is the oldest of the four major professional sports leagues in the United States and Canada, in fact the oldest professional sports league in the world. A total of 30 teams now play in the American League (AL) and National League (NL), with 15 teams in each league. The AL and NL operated as separate legal entities from 1901 and 1876 respectively. After cooperating but remaining legally separate entities since 1903, in 2000 the leagues merged into a single organization led by the Commissioner of Baseball. The organization also oversees minor league baseball leagues, which comprise about 240 teams affiliated with the major-league clubs. With the World Baseball Softball Confederation, MLB manages the international World Baseball Classic tournament.
Baseball's first professional team was founded in Cincinnati in 1869. The first few decades of professional baseball were characterized by rivalries between leagues and by players who often jumped from one team or league to another. The period before 1920 in baseball was known as the dead-ball era; players rarely hit home runs during this time. Baseball survived a conspiracy to fix the 1919 World Series, which came to be known as the Black Sox Scandal. The sport rose in popularity in the 1920s, and survived potential downturns during the Great Depression and World War II. Shortly after the war, baseball's color barrier was broken by Jackie Robinson.
New York City is for many sports fans synonymous with the New York Yankees and their logo. The team is noted as having been the team of many of the all-time greats in the history of the game, and for having won more titles than any other US major professional sports franchise. The city was also host to two other highly popular baseball teams in the National League, the Brooklyn Dodgers and the New York Giants, before their transfer to California beginning with the 1958 season. The Yankees' chief rivals, the Boston Red Sox, also enjoy a huge following in Boston and throughout New England. The fierce National League rivalry between the former Brooklyn Dodgers and New York Giants was transferred to the West Coast when the teams became the Los Angeles Dodgers and the San Francisco Giants, and California has always been among the US states which have supplied the most players in the major leagues. Philadelphia sports fans have rooted for the Phillies since 1883, as they are the oldest continuous, one-name, one-city franchise in all of professional American sports. Philadelphia Phillies fans are known for their rabid support of their team throughout Philadelphia and the Delaware Valley, and have famously been dubbed as the "Meanest Fans in America".  Chicago sports fans also avidly follow the Chicago Cubs and the Chicago White Sox despite the comparative lack of success for the teams over their histories.
The 1950s and 1960s were a time of expansion for the AL and NL, then new stadiums and artificial turf surfaces began to change the game in the 1970s and 1980s. Home runs dominated the game during the 1990s, and media reports began to discuss the use of anabolic steroids among Major League players in the mid-2000s. In 2006, an investigation produced the Mitchell Report, which implicated many players in the use of performance-enhancing substances, including at least one player from each team.
Today, MLB is composed of thirty teams: twenty-nine in the United States and one in Canada. Teams play 162 games each season and five teams in each league advance to a four-round postseason tournament that culminates in the World Series, a best-of-seven championship series between the two league champions that dates to 1903. Baseball broadcasts are aired throughout North America and in several other countries throughout the world. Games are aired on television, radio, and the Internet. MLB has the highest season attendance of any sports league in the world with more than 74 million spectators in 2013.
Baseball in the United States