The Oakland Athletics, more commonly known as the Oakland A's, are original members of the American League. Founded in Philadelphia, they moved to Kansas City after the 1954 season, and to Oakland in 1967.
Play in O.co Coliseum (formerly Network Associates Coliseum and before that, Alameda County Stadium), one of the most pitcher-friendly ballparks in the majors. Despite this, Oakland has been better known for their hitters - Reggie Jackson, Rickey Henderson, Jose Canseco, Mark McGwire, and Jason Giambi - than their pitchers. However, the only two numbers retired by the A's are 27 for Catfish Hunter and 34 for Rollie Fingers - both pitchers.
Charles Finley, owner of the club from 1960 to 1981, was responsible for the move to Oakland and many other oddities in baseball during the 1970s. He attempted to introduce gold bases and orange baseballs, and after a disappointing 1975 season, tried to sell Vida Blue, Jackson, Fingers, Joe Rudi, and Ken Holtzman - the team's five best players - for cash.
The A's have been very successful in their years in Oakland, making the playoffs 10 times, winning the AL pennant in 1972-74 and 1988-90 and the World Series in 1972-74 and 1989, when they swept their neighbors the San Francisco Giants. That series was interrupted by an earthquake which damaged Candlestick Park, the Giants' home.
The general manager in the late 1990s/early 2000s, Billy Beane, was one of the guys responsible for the Moneyball philosophy and the rise of sabermetrics.
The A's mascot is a white elephant. In 1902, John McGraw insulted Connie Mack, then manager of the A's, by calling his team the White Elephants. Mack appropriated the image and responded by winning the American League pennant that year.