In the early 1970s, Major League Baseball players seldom, if ever, wore facial hair. The practice had been widespread in the 19th century, but by the early 20th century it was rare for a player to sport a mustache or beard. As detailed in the book Mustache Gang, Oakland Athletics owner Charlie Finley decided to hold a mustache-growing contest within his team. When the A's faced the Cincinnati Reds, whose team rules forbade facial hair, in the 1972 World Series, the media dubbed the series as "the hairs vs. the squares". Thanks in part to the on-field success of the A's in the early 1970s, along with changing fashions, facial hair has again become very common among baseball players.