THE DEVIL AT LARGE, Erica Jong on Henry Miller (Chatto and Windus, $192). HENRY Miller would have loved this highly unorthodox voyage around his life: it breaks every rule in the biographical book. It has no pictures in the middle, begins at the end of his life and leaps uninhibitedly back and forth between dates, events and places, making several detours through a quixotic compendium of personal memoirs, treatise, expositions and apologia. Yet for all these liberties, it is far more reliable a memoir of the writer and playwright than the partial, hostile and merely cosmetically accurate biographies of Miller which preceded it. Erica Jong and Henry Miller began corresponding with each other in 1974 when he wrote her a fan letter in praise of Fear of Flying and the explosion its recent publication had ignited; he called it the female counterpart to Tropic of Cancer. Their friendship lasted for the rest of Miller's life and still endures in Jong, having long survived the publicity godsend exploited by the media under the ''dirty old sage and young Wife of Bath'' label. This book is not the product of the Jong-Miller mutual admiration club that one might have expected in the light of their firm friendship. Indeed, one of its strengths is that Jong never allows her fondness for Miller to impair her critical detachment inappraising his work. In 1961, Miller and his publisher successfully defended themselves against their alleged conspiracy to corrupt public morals with ''a certain obscene, lewd, lascivious, filthy, indecent, sadistic, masochistic and disgusting book'' - Tropic of Cancer. It was a pyrrhic victory, and the effect of Miller's continual involvement in obscenity proceedings was, as he predicted, to turn him into the ''king of smut'' and to doom him with a notoriety that eclipsed the importance of what Jong holds up as his best book: the visionary Colossus of Maroussi. Jong's main motivation in writing the book is to justify the ways of Miller to an unsympathetic audience, but she faces an uphill struggle with an especially steep gradient: Miller's own autobiography, which he decorated with pictures of himself and naked women and probably wrote out of sheer devilment, only went to reinforce his image as sexual opportunist and ''f***about misogynist''. It is hard to gauge the degree of truth in the rumours surrounding Miller. He despised facts and invented himself and his life in the same way that he invented women to fall in love with: by creating an ideal and fitting the person around it. What is true is that Miller preserved his literary integrity to his financial detriment: a bowdlerised Tropic of Cancer would have gotten the book published in the US, but he never capitulated to Penguin's constant pressure to edit the sex. He was, besides, content for Tropic of Cancer to be available only in Paris beneath the covers of Jane Eyre; when it finally appeared in the US, he lost his privacy to a constant stream of fans. Also, he frequently rejected requests to hack for Hollywood. The irony of Miller's posterity is that he could not have written pornography if he had been paid to - which he was, while poverty-stricken in Paris. He was fired after a week for being ''too poetic''. Jong is too finely attuned to what made Miller tick, both professionally and personally, to join battle against him with the militants. Indeed she argues convincingly that by shocking the reader into confronting what is already well-established in the unconscious, Miller's writing is ''a force for feminism''. Miller himself was vociferous in his defence of Fear of Flying - which was primarily Jong's attempt to reconcile her sexuality to her intellectuality - and strong in sympathy with her feminism: he knew what it felt like to be deliberately misunderstood. Vladimir Nabokov piercingly observed in his afterword to his masterpiece Lolita that good literature can never be pornographic, since it does not leave room for true imagination: ''Action has to be limited to the copulation of cliches. Style, structure and imagery should never distract the reader from his tepid lust''. The sex scenes in Tropic of Cancer are few and far between, but entirely in keeping with the book's agenda, which is to transport the essence of experienced life on to the page with all its gory bits intact. They are not pornographic. Miller's writing is full of blemishes and purple prose. Like D. H. Lawrence, he wrote everything in a spontaneous outpouring of feeling and never bothered to edit it. Jong recognises all Miller's shortcomings, literary and personal, for what they are. Ultimately, her triumph is to convey the salutary effect of Miller's work and the breadth of his vision as it ''strains beyond the fame of the picture''. Nothing demonstrates this better than his letters to Jong, which, written in his 80s, still overflow with an expansive passion for the whole of life. Jong is what she calls a ''First Amendment fundamentalist''. This book is a fiery fillip for freedom of speech, a shot in the arm for feminism and a kick in the backside for literary hypocrisy. To paraphrase her book: read Miller.