I Kill Giants by Joe Kelly and illustrated by JM Ken Niimura

Barbara Thorson is not your average fifth grader. Oh, she may look like just another bespectacled, funny-hatted munchkin, but don't get her mad because she just might smite you with her mighty hammer, Coveleski (named for an obscure left handed Phillies pitcher who single handedly defeated the New York Giants in a 1908 playoff race). [...:]