Even if you're an avid history buff, you've probably never heard of this disreputable cast of characters: A drunken, ne'er-do-well cop who abandoned his post at Ford's Theatre, giving assassin John Wilkes Booth unchallenged access to President Lincoln; a notorious Kansas quack who made millions by implanting billy goat testicles in gullible male patients; and America's worst female serial killer ever. These are three of the memorable but little-known...