Oddly, the jacket shows eleven-year-old Priscilla ""Pete"" Penney swinging a mean bat--when it's pitching that, thanks first to leprechaun Mike McGlory, makes her a Little League standout. But this is a patchwork in any case, contrived of stock plot elements, diversionary interludes, and enlightened ideas. Leprechaun Mike pops up when ""tomboy"" Pete tosses off one of her Irish-name fulminations; grants her wish for an un-hittable curve ball; and warns her never to say his name again, or he'll vanish. Using that miraculous curve only sparingly, Pete is soon top pitcher on her major/minor league team--to the surprise of her dismissive big brother and the team girl-goad--and even gains a major league berth. But meanwhile she's wondering how far she'd get without the ever-needling Mike who--in the book's funniest bit--has ""become a regular Billy Martin."" Then, in a tiff, Pete shouts the forbidden name and--with little auctorial forewarning--comes through in the ensuing games (unspectacularly) anyhow; she's having fun, at this point, win or lose. Mike turns up for a final Wrigley-Field salute, but the book has already gone off in assorted irrelevant directions (a passion for kite-flying, a much-touted trip to the zoo) and dissipated the rest of its energy in observations on the improved, still-imperfect lot of a girl baseball player. Plus: intimations that playing baseball need not make one less a girl. Timely hokum.