Major league baseball is a popular game played in thirty host cities throughout the United States. Of the 30 teams, 14 compete in the American League (AL) and 16 compete in the National League (NL). Other than the number of teams in each league, there are a few other minor differences between the leagues and one major difference.

In the first World Series, played in 1903, the Boston Pilgrims (AL) defeated the Pittsburgh Pirates (NL). In World Series play, the AL holds a decided advantage, having won 58 championships to the NL's 41. The first All-Star game was held in Chicago's Comiskey Park in 1933 as a means for baseball to showcase its star players. Over the years, the NL has won 49 All-Star games and the AL has won 31. Unfortunately, the 2002 game ended in a tie, the lone time time that has happened in All-Star history.

The NL was the first league to integrate as Jackie Robinson was the first African-American player to play major league baseball. He broke the color barrier in 1947 as a second baseman for the Brooklyn Dodgers. The AL followed suit a few months later as Cleveland's Larry Doby became the first black player in that league.

The primary difference between the AL and NL lies in the fact that the American League allows a designated hitter while the NL does not. A designated hitter (DH) is a player allowed to bat in place of the pitcher. As a result of using the DH, AL teams tend to average more runs than do NL teams as they have an additional solid batter in their lineup. AL pitchers never bat. The DH was introduced during the 1973 season. On April 6, 1973, to be exact, New York Yankee player Ron Blomberg became the first DH to ever bat in a major league game. In the NL, pitchers still bat and while they may not be good hitters, they are expected to be able to make an effective bunt when called upon.

During World Series play and inter-league play, where AL and NL teams play each other, the rules of the home team apply. For instance, if a game is held in an AL city like Boston, the DH rule is in effect and both teams are allowed to use a designated hitter. When games are held in NL stadiums, neither team is allowed a DH. Baseball purists would like to see the DH position done away with, but it is now entrenched in the AL and is unlikely to be pushed aside.