Crossing the Line — Barbara Belford

Billy's family has fallen on hard times, what with his da hospitalized after the war and his ma barely scraping by. But it's no hardship for him when there's not enough money to pay the tuition for Nativity of Our Lord, the private Catholic school everyone in his neighborhood attends. Billy's not big on education.

When he transfers to James Ward, a Chicago public school, he finds out there's a big difference at public school: the kids aren't all Irish -- in fact, they aren't even all white. It isn't long before Billy's found a new best friend in Foster, another fifth grader who also doesn't have any money, loves baseball, and just happens to be black.

Billy is pretty sure skin color doesn't matter. Not when he and Foster are just horsing around, playing baseball, working on the docks of the canal, and building a raft at their secret hideout on Bridgeport's Bubbly Creek. But in the Red Summer of 1919, it does matter.