This is the tenth book in the "Baseball Card Adventure" series by Dan Gutman, but the first one I have read. They are written for younger readers, maybe 3rd or 4th grade, but I really enjoyed it.
The books are about a boy who is able to travel in time using baseball cards, and he sets out in this book to save Roberto Clemente's life by convincing him not to get on the airplane in 1972. The only Clemente card he could find, however, was from 1969, so he had to take a detour through Woodstock before finding Clemente.
It's an entertaining read, and fairly quick (I was able to get through it in a few hours during downtime at work). After reading a more historical account of Clemente, I intend to seek out other Dan Gutman "Baseball Card Adventure" books, and hope they are just as fun.
The players he has featured so far are Abner Doubleday, Babe Ruth, Honus Wagner, Jackie Robinson, Mickey Mantle, Satchel Paige, Shoeless Joe Jackson, Jim Thorpe, and Ray Chapman.