Hemingway's Boat is a biography of Ernest Hemingway the sportsman - even Hemingway the athlete, as the author Paul Hendrickson says without embarrassment. His aim is to create a link between Hemingway and his fishing boat that is as solid as the link between Louis Armstrong and his horn - which is nuts, but evidence of the importance sports assumes in American literary life. American writers have an obsessive relation to sport. Baseball, basketball and American football are difficult to understand because they are enclosed worlds. Boxing has assumed an importance that bypasses understanding for more obscure reasons (race, masculinity, a desire to be punched in the face). But there is also a small group of sports that are unintelligible in and of themselves; in fact, so awe-inspiringly unintelligible that they represent a grand American mystery. I am talking, of course, about bodybuilding, Monster Truck Derby and especially marlin fishing - the great obsession of Hemingway, the king of the grandiosely pointless pastime. Hemingway wanted to be remembered for his life rather than his writing, Hendrickson argues, backed by numerous quotations. First and foremost, this was a sporting life. In the Twenties, Fitzgerald has Gatsby address everyone as "sport," reflecting a world where rich men dedicate themselves to a life of sailing and hunting. These are "worthless sporting characters," attacked by Hemingway in his fiction, and in real-life with his fists in drunken rages. But rather than reject their interests, Hemingway hopes to outdo them. He took $30,000 from the father of his first wife to stage a grand African safari. Then, back home, he switched to big-game fishing, hunting off the Florida Keys before moving permanently to Cuba to snare the fish on their way from the Caribbean to the Bahamas. Big-game fishing is a quintessential American sport. Like basketball, it is a modern invention, devised by the wealthy marine biologist Charles Frederick Holder in 1898. It is a sport that depends on machinery: pleasure boats with engines. Hemingway picked his from a catalogue, a model known as the Playmate. Hendrickson assures us Hemingway would have hated this name. I doubt it. Hugh Hefner didn't seize on the word Playmate because it was a turn-off to middle-aged, sex-obsessed men. Inevitably, this is a sad story. How could it not be? In no world could Hemingway's pursuit of blood and purity from atop a floating gin palace make sense. Hemingway was already being parodied and pilloried by 1934 when he bought his boat. His stubborn pursuit of the sporting life only fuelled the mockery and probably hastened his decline into the hollowed-out celebrity joke-figure he had become by his suicide in 1961, at the age of 62. Hendrickson tries to imbue Hemingway's decline with a grandeur, inevitably slipping into the kind of fake Hemingwayese that no one seems able to avoid when writing about Hemingway. How is it that the novelist succeeds in sounding laconic and minimal, when the actual words are so ornate and overblown? It is a mystery, and in the end the reason that Hemingway is an original. Hendrickson wants to go further by arguing that there is also a grandeur in the life, if only we understood Hemingway's sport of choice, but isn't it rather like arguing that Elvis was at his best when he was wearing that karate-suit on stage in Vegas? by Paul Hendrickson 534pp, Bodley Head T £18 (PLUS £1.25 p&p) 0844 871 1515 (rrp £20)