Could be the script of a 1930's movie serial, though it is purportedly the true story of a young Briton's trek through the Amazon jungle. What with its intrepid, blond, blue-eyed protagonist; half-crazed prospectors; sinister police officials; tawny Indian maidens; treacherous native guides; curare-tipped darts; piranhas; thrashing crocodiles and rampaging rivers, the narrative incorporates nearly every cliffhanging clichÃ‰ beloved by Saturday matinee movie audiences 50 years ago. In 1983, age 23, Allen set off from his London bed-sitter, determined to traverse the Orinoco delta and from there to reach the mouth of the Amazon, an itinerary stretching 1,500 miles, ""as the vulture flies,"" through unexplored territory. Having arrived in South America, he dawdles awhile in the flyblown outposts of ""civilization,"" meeting a cast of characters straight out of B. Traven. These are the most entertaining portions of his yarn. From there, he's off to live among the Indian tribes, where he becomes involved in the usual seriocomic contretemps favored by explorer-writers. He arouses the interest of a local damsel; there's something about his shoelaces she can't resist. She's banished by the tribe; he's forgiven. Once deeper into the jungle, things get predictably worse: Carib tribesmen insist he wrestle a wild pig or die; another ""romantic"" imbroglio, this time with a chief's daughter; much slogging through the steaming wilderness until he discovers his guides intend to murder him. He flees, accompanied only by a mutt picked up along the way. Plunging ahead, he ""lives off the land,"" i.e., consuming locusts, termite grubs and eventually his canine companion. After seemingly interminable complications--exhaustion, fever, hallucinations--he finally staggers out of the undergrowth, eager only for ""the stench of exhaust fumes."" Described as ""hilarious"" and ""daft,"" Allen's overextended adventure tale is, in fact, plodding in its execution and barely credible in the events it describes. Enjoyment will depend on the reader's patience and capacity to suspend disbelief.