The agitation was there from the beginning. Upon birth he inherited a wastrel father, a clinging mother, and, bane of his existence, a club foot; for compensation there were his personal good looks and a titled inheritance. As he noted of his own favorite poet, the hunchbacked Alexander Pope, it is the "unhappy dispensation of Nature that deformed persons ... are born with very strong passions. They are condemned to combat, not only against the passions which they feel, but the repugnance they inspire."

His own passions, he would later write, "were developed very early, so early few would believe me ..." The age was nine, the seductress was a strange nursemaid who, according to the account of one friend, "used to come to bed with him and play tricks with his person." Privilege and later fame brought endless opportunities for him to play with others. Following the publication of the first two cantos of his breakthrough poem, Childe Harold's Pilgrimage, Byron said he "awoke one morning and found myself famous." For the rest of his life, fame, outrageous productivity and scandalous affairs would multiply, with no boundaries on sex or age. Aside from numerous short-term sprints, these included an openly adulterous affair with Lady Caroline Lamb, not the blue-eyed one cited above, but a trail-blazing gender-bender and certified nutcase; a romp with one middle-aged society matron, Jane Harley, Lady Oxford; an almost certainly incestuous relationship with his half-sister Augusta Leigh; a disastrous marriage to the pious Annabella Milbanke; a fling with Claire Clairmont, step-sister of Mary Shelley and Percy Shelley's occasional girlfriend; and, in his last years, a heated but rather tender romance with Teresa Guccioli, wife of an Italian nobleman. Among young men, there were the chorister John Edleston, and Byron's page, Robert Rushton. These are just the ones people write about.

Byron died in 1824 at 37, not long after settling in Greece and lending himself and his money to the country's independence movement, yet he was as strong a presence as anyone in the arts and letters of the 19th Century. Writers, artists and musicians all fell under the spell of both his poetry and recurring speculation about his life. Poe couldn't stop quoting him. Eugene Delacroix put Byron's poems on canvas and took to dressing like him. The dark, brooding "Byronic figure" — loner, outcast, corrupt Narcissus — was the Big Bad Wolf in one 19th Century novel after the next.

The charm hasn't died. In the last decade alone, there have by my count been at least twelve full or partial biographies of Byron, and the last few months have delivered two new examples of both. Both have a bit of a "truth problem." Biographers of the famous dead toil under a burden of delivering fresh revelations, and long-dead subjects can make it temptingly easy to come up with unprovable theories. This is the downfall of Fiona MacCarthy's big comprehensive life. David Crane sets his sights a little lower, and acquits himself reasonably well.