Fans mob Bob Skinner after his walk-off homer against Cincinnati on Easter Sunday 1960. Among the fans, Pete Peterson, in the dark shirt with his hand on another fan's back.(Pete Peterson)

Baseball doubleheaders were a part of the Major League Baseball landscape for decades, but now they’re almost non-existent, barring rainouts.

In his latest edition of Reading Baseball, Pete Peterson asks the question, what is a doubleheader?

Reading Baseball is a series of essays and commentaries by Richard “Pete” Peterson, author of Growing Up With Clemente and editor of The St. Louis Baseball Reader.