Allen Barra is back withBrushbacks and Knockdowns, his newest retrospective of baseball history and folklore. Barra, whose weekly sports column "By The Numbers" earned him millions of readers inThe Wall Street Journal, offers solid answers based on exhaustive research and analysis. But Barra risks inciting barroom riots with essays covering such topics as "Who was a better hitter, Babe Ruth or Barry Bonds?," "Is Barry Bonds been the best player over...