When Harold met Shelley Annabella

Byron was the first pop star. If the most significant cultural shift of the early 19th century was a shift in public attention from works of art to the lives of artists, he was central to that process. As the heir to a title, Byron was called on from birth to play a public role - but as the heir to no money, he couldn't play the one expected. He was cavalier about his literary leanings, as though afraid that writing were simply a higher form of being in trade, but it was through writing that he shaped for himself a new form of public identity.

Phyllis Grosskurth's account of Byron's background and childhood is dominated by the poet's mother. His father was a spendthrift roue who died in exile when Byron was four. The marriage had been bleakly miserable and left no financial protection. Handicapped by a club-foot, the child was deeply self-conscious: his mother's gauche approach to her English relations constantly betrayed her provincial Scottish upbringing, and although Byron seems never completely to have shaken off his accent he did all he could to erase his nationality. Her devotion to him was far greater than he consciously acknowledged, but may partly explain the irresponsibility shown by his having to leave Cambridge early with debts of pounds 25,000 - a quite extraordinary sum in any age. An essential insecurity meant that he always had to live like a lord.

Byron's circles at Harrow and Cambridge were bisexual in orientation, and his early travels in Greece and Turkey have a strongly homosexual cast. Grosskurth believes that he wasn't very highly sexed, and that his promiscuity was a search for the home he never felt he had, but this is not very persuasive. Behind her theory of the search for a home is the iron hand of Freudian determinism, and it seems weirdly inappropriate to a being as self-creating as her subject.

However, Grosskurth writes sympathetically about Byron's affair with his half-sister Augusta Leigh and about his marriage to Annabella Milbanke. If a reference to women "twittering" about the poet's appalling marital behaviour seems one-sided, she does bring out well how Annabella, under her mother's aegis, hardened into an avenging fury. Byron's major motives for marriage were to escape the looming scandal of incest and to secure his finances: he failed in both. He was already famous, the overnight success of Childe Harold in 1812 having assured this. The poem's morosely introspective hero was taken to be a mask for the poet, and Byron's own personality was now a matter of public fascination.

Byron's later years in Italian exile, his love-life and his involvement with the Shelley circles are all well documented here. One of Grosskurth's most successful re-creations of the poet's world is her account of his involvement with the cause of Greek independence from Turkey, and his journey to Missolonghi. "The role-playing - even in the most responsible moments - broke down in the effort to believe and to behave as though everything were real, that he actually had a role to play although it was never to be revealed to him", she writes. Her description of Byron's death-agonies at the age of 36 is haunting.

Nonetheless, this is a book without a plot. If we want to know where Byron was or what he was doing on a particular day, it is a very helpful study, and Professor Grosskurth's work on the Lovelace Papers enables her to give a much fuller and more credible picture of Annabella than we have had before. The problems begin when we want to understand Byron himself, as the motivation she offers simply doesn't make sense. She does, though, offer a number of tantalising hints which point to a very different picture.

Byron's "only sense of himself", she writes, was "formed by the impression he made on other people" (hence his frequent dieting, because he was prone to obesity). This is the key to his story, and it explains something Grosskurth is baffled by.

On 19 February 1814, Byron saw Edmund Kean play Richard III, and was overcome. "Constantly he talked about Kean and about Richard. His resemblance to Hamlet's wavering uncertainties was far more marked, but it is intriguing that he could see a reflection of himself in Richard's evil twisted self", we are told. In November of the same year, at his first meeting with his prospective in-laws, Byron is found talking about Kean's acting.

In fact, Byron's fascination with Richard III makes perfect sense. Although his tendency to a passive drifting with events was at times marked, Byron was not a Hamlet. Hamlet resists and resents the indignity of being drawn into his father's ghost's revenge-plot, an action which must circumscribe his mental freedom. He wants to remain remote from the world, where Byron was determinedly worldly. Richard, on the other hand, is a self-making and self-aware villain who chooses to become what he does. Byron was drawn to him because he too wanted to shape his own destiny at whatever cost. He seems to have suffered from a free-floating sense of guilt, perhaps caused by his failure to respond to an excess of maternal love. By sleeping with his half-sister, he could give that guilt a real cause, and Phyllis Grosskurth's book makes it clear how central that relationship was.

She also suggests that his love for Pope's poems was "enhanced by the fact that Pope was crippled". Maynard Mack's biography of the latter points out that more painted, printed or sculpted images were made of Pope than of any other non-royal person in 18th-century England. Pope took great care that his deformity should be concealed, and it seems likely that his manipulation of his image was the precedent for Byron's own.

Byron's comic masterpiece, Don Juan, is a continuation of the Pope tradition of loving satire (Byron loves Don Juan just as Pope loves Belinda in The Rape of the Lock) and the fullest expression of Byron's pride in his virtuosity. The search for rhyme is an existential challenge, and Byron was far closer to the existential man who would emerge later in the century - in Dostoyevsky and in Nietzsche - than Phyllis Grosskurth's rather pedestrian book can show.