This is one of those books that gets compared to "Catcher In The Rye" that doesn't make the comparison look ludicrous.
I noticed Wilker's work on his blog, Cardboard Gods, which used to be part of a literate baseball blogging collective called the Baseball Toaster. Wilker simply picks out baseball cards from his boyhood collection, and masterfully melds the player's expression, or reputation, or batting stance, or something about the card into a autobiographical story from his life.
Wilker's writing is gorgeous, and, though you don't need to like baseball to enjoy the book, you will enjoy it more if you do. I cannot recommend the book highly enough-by far the best I've read this year, and I am confident I will reread it in years to come.