Tuesday books: Two lives of the greatest lover

CASANOVA, OR THE ART OF HAPPINESS BY LYDIA FLEM, PENGUIN, pounds 12.99 CASANOVA BY ANDREW MILLER, SCEPTRE, pounds 14.99

"CAREFUL I have - fragile - mementoes," the aged, impecunious Casanova shouts as his portmanteau is thrown from a hotel balcony in Tennessee Williams's play Camino Real. Two new books, a novel and a free-wheeling biography, sift through the contents of that baggage.

Both Andrew Miller and Lydia Flem frame their accounts with Casanova's final employment as librarian to the Count Waldstein, in Bohemia. Miller's fictional version opens with Casanova instituting a La Boheme-style conflagration of his papers, only to be assailed by the smell of some ancient letters. Flem closes with an almost Proustian sense of recovered time as Casanova transmutes experience into words by writing his memoirs, declaring that "true happiness is the one offered by reminiscence".

Flem's sparkling precis of Casanova's life offers delightful portraits of his greatest loves (nuns and noblewomen; mothers and daughters; a fake castrato), and tantalising glimpses of his adventures. (He saves a dying nobleman; escapes from the Doge's prison; is nursed back to health by a mysterious mistress). A professional psychoanalyst, Flem removes Casanova from the mattress to the couch, finding the key to his character in his relationship with his mother, the beautiful but distant actress Zanetta.

Flem portrays him as an honorable man with a genuine concern for the women he beds ("When he parts with a mistress, he has the decency to arrange a happy sequel - marriage, dowry, theatre engagement").

He emerges as the complete antithesis of his supposed fictional counterpart, Don Juan. This is a highly imaginative biography, free from the constraints of chronology, replete with insights and charm.

Flem subtitles her book "the art of happiness" and her Casanova is a sunny soul who "makes a perpetual carnival of his life". The one exception is "A day of despair in London when he considered throwing himself into the Thames because he had been deceived by La Charpillon, a young prostitute." It is on this deception that Andrew Miller focuses, as he explores the 38-year-old Casanova's nine-month stay in England in 1763 and 1764.

The bundle of letters which causes such consternation to Miller's Casanova is from La Charpillon, a courtesan who is her "family's sole commodity... though every year her value must decrease". Casanova becomes infatuated with the girl, who realises that she can gain more from him by withholding her favours than by granting them.

Her intention, jocularly expressed but mercilessly enacted, is to punish Casanova by "making him fall in love with me and then torturing him". Miller charts the course of their relationship through the fleshpots and pleasure-gardens of London, the maze at Hampton Court, a visit to the country, and the courts.

Casanova is a deeply disappointing second novel from the author of Ingenious Pain. There is no sense of personal impetus behind the writing, which offers a rehash of well-known images and themes.

True, Miller darkens the portrait of Casanova familiar from his own memoirs; but literature is littered with the confessions of self-disgusted libertines. There are many verbal felicities, such as La Charpillon's aunt "smiling like an abbess he once knew who took in rich girls for abortions," but an equal number of crudities - modern colloquialisms such as "cruised her" and "walk-in wardrobe", or a reference to the demi-monde, a phrase coined in 1855.

A reading of Casanova's own account of his London adventures explains why Miller's seems so secondhand. In an note at the end, Miller acknowledges his debt to the original, but he seriously underestimates its extent. Several episodes (notably Casanova's attempt to escape La Charpillon's influence by working as a labourer, and his removing her entire family to the country) are his own invention, as is his development of Casanova's supposed meeting with Dr Johnson; but these are incidentals.

Elsewhere, not only the basic plot, but characters, anecdotes and indeed the entire emotional thrust of La Charpillon's cat-and-mouse game are taken directly from the Histoire de Ma Vie. Miller sticks extremely closely to Casanova's text from his initial visit to his ex-mistress Mrs Cornelys, through his affair with his Portuguese lodger, Pauline, his association in debauchery with Lord Pembroke, and his discovery of La Charpillon with her hairdresser. Even his choicest anecdotes - such as the victim of a boxing match being refused aid because two men were betting on his chances of survival, and the fake castrato's anatomical device to escape detection - are taken straight from the original.

One can only presume that Miller saw in Casanova a second 18th-century subject with which to repeat the success of his first, and hope he gives more scope to his own proven powers of imagination in his next book.