The Brooklyn Dodgers tantalized their fans throughout the '40s and early '50s, winning the National League pennant six times but failing to become world champions. One of the millions of hearts that beat with every pitch and broke with every loss belonged to Doris Helen Kearns, growing up in Rockville Centre, N.Y., in a baseball- crazy neighborhood where Jackie Robinson, Joe DiMaggio and Bobby Thomson were kings. Time and again young Doris--now the historian Doris Kearns Goodwin '64--watched "dem bums" lose the biggest prize in baseball, and time and again she embraced the Brooklyn Eagle's perennial headline: "Wait Till Next Year."     "Next year" finally came in 1955, when the Dodgers defeated the hated, storied Yankees in seven games to win the World Series. Two years later, in September 1957, the team played its last game at Ebbets Field. The Dodgers were transplanted to Los Angeles by owner Walter O'Malley in a move that can still make former Brooklyn fans speechlessly angry. (O'Malley even tried to trade Robinson to the Giants--the Giants!--but the Dodger superman chose retirement instead.)     In 1949, Goodwin, who is now a Red Sox fan ("a dubious progression," she admits), began keeping scorecards on every Dodger game in a book given to her by her father. She also became fully aware at about that time of her mother's illness, angina, which caused Helen Kearns debilitating pain and made her look more like her young daughter's grandmother than her mother. "Every night, I would fall asleep with the prayer that while I slept the lines on my mother's face would vanish, the leg that now dragged behind her would strengthen, her skin would lose its pallor," Goodwin writes. They were able to share the joy--there's no other word--of the Dodgers' first championship, but by then Helen Kearns was seriously ill. She died in 1958, two months before the Los Angeles Dodgers' home opener.     Goodwin is too fine a historian to wrap any story--even her own--in gossamer, which sets Wait Till Next Year well apart from the mass of cloyingly self-serving celebrity autobiographies. The book is a memoir of a singular, mostly happy, childhood; but it also is the story of a peculiar time in American history, when the country was on the lip of war and upheaval, the civil rights movement was beginning to stir--and a baseball team could capture a person's soul.