A century before Kirby Puckett led the Minnesota Twins to World Series championships, Minnesota was home to countless talented African American baseball players, yet few of them are known to fans today. During the many decades that Major League Baseball and its affiliates imposed a strict policy of segregation, black ballplayers in Minnesota were relegated to a haphazard array of semipro leagues, barnstorming clubs, and loose organizations of all-black teams—many of which are lost to...