In public estimation, sloths have undergone an astonishing transformation in the course of the past few years. Thanks largely to YouTube clips posted by the sloth orphanage in Costa Rica, sloths have attracted a vast audience of admirers. Instead of seeing them as ridiculous anachronisms of which we know little, they have turned into creatures considered by many to be the most endearing on earth. Over much the same period, scientific investigations have also changed our view of sloths. No longer are they seen as total misfits in the modern world but, in the words of one specialist sloth investigator, they are "masters of an alternative lifestyle." This wonderfully entertaining book reveals the fascinating history of the sloth, from the prehistoric ground sloth to modern pygmy sloths in Panama, explores the current state of the science of sloths, and reveals the truth behind sloth behavior.