In Pass the Butterworms , Cahill takes us to the steppes of Mongolia, where he spends weeks on horseback alongside the descendants of Genghis Khan and masters the "Mongolian death trot"; to the North Pole, where he goes for a pleasure dip in the 36-degree water; to Irian Jaya New Guinea, where he spends a companionable evening with members of one of the last head-hunting tribes. Whether observing family values among the Stone Age Dani people, or sampling...