In baseball, there is a set batting order and the players come to the plate in that exact order throughout every game. The one who bats first is known as the leadoff man. What people want in a leadoff man has evolved over the years, from a smaller player who annoys the pitcher into a base-stealing monster and now many leadoff men are power hitters.
Consider this "everything you ever wanted to know" about the leadoff man. Matt Snyder discusses the history and evolution of the leadoff man before diving into the stats and how they've long been applied to leadoff hitters. There is a fun exercise on which players could have hit leadoff throughout history, if the evolution process was a bit faster. The best and most fun moments have their own chapter and then there's a ranking of the greatest leadoff hitters who ever played Major League Baseball.