A quest to find the real seafarer that inspired Defoe's fictional hero is the motivation behind this unusual travelogue. As he follows in the wake of 17th-century pirates and adventures, Severin proves that the travels that Defoe modeled his tale after were in the Caribbean, not the Pacific. He also challenges the long held assumption that Alexander Selkirk was Crusoe's real-life counterpart. A master of retracing old journeys, Severin is also the author of The Brendan Voyage (ARC77) and The Spice Islands (INS82).  (PAC130, $16.95)