Series of novels and short stories by Peter O'Donnell, spun off from his long-running adventure comic of the same name. Modesty Blaise is an orphan with a Dark and Troubled Past who was head of a criminal syndicate before she was 20, and retired wealthy before she was 30. Willie Garvin is a multi-talented Cockney former street kid who became Modesty's trusted right-hand man and followed her into wealthy retirement. Retirement was boring, so now They Fight Crime. (Only crime that's unusual enough to attract their interest, though -- or nasty or personal enough to attract their anger.)