The first baseball stamp was issued in Cooperstown in 1939 marking the (contested) invention of baseball by Abner Doubleday in that New York town in 1839.
Stamp Collector in Chief at the time, President Franklin Roosevelt said he wished every boy in the nation could get a first day cover of the stamp. To this end it was arranged that postmasters nationwide would collect self-addressed envelopes and the 3 cents for the stamp and send them on to Cooperstown.
Could such a simple plan work today? Probably not. You'd have to get a few corporations to underwrite it -- and of course their logos would have to appear somewhere on the cover. And then what about Major League Baseball? If you say the name of one of their teams in your sleep you'll wake up to find a notice in your mail the next day informing you of your duty to pay a licensing fee. By the time the boys of the nation got that baseball first day cover today (post Women's Lib we will allow girls to order them too -- hey, a buck is a buck) they would have to cough up about twenty dollars for the privilege of being taken out to the ball game. Or is that taken to the cleaners?
In any event, free is good and we thank the American Philatelic Society for offering. Collectors into baseball stamps can find their mini-album here.
Also check out the other APS freebies here.