As all the world knows, Joseph Kennedy had four sons. The first, Joseph Jr, was killed in action at 29 in 1944. The second, John, president of the United States, was assassinated aged 46 in 1963. Robert, the third, was murdered five years later, aged 42. Only Edward, the youngest, was spared to die in his bed of natural causes, aged 77, in August 2009. And only Ted, therefore, left a volume of Kennedy memoirs. For that reason alone, this book (True Compass A Memoir by Edward M. Kennedy) stands out, even in the evergreen and still-multiplying forest of Kennedy literature.

Politicians write memoirs for a variety of reasons. For money most of all, for esteem, to settle scores and defend their records, or simply because they can, sometimes extremely well. All of the above apply in some degree to Ted Kennedy's memoirs. But these are unusual in that they have been consciously designed as Kennedy's public memorial. Begun before he was struck down by a brain tumour in May 2008, they were completed - and crafted - in the knowledge that they would speak directly to Barack Obama's America from beyond the grave. Published less than a month after his death, these memoirs are therefore a supremely political act.

One turns first, of course, to the pages that deal with the catastrophic event to which his raucous, glamorous and fateful life seemed to be building and which shaped the second half of it the Chappaquiddick crash of 1969, in which Kennedy left Mary Jo Kopechne to drown in a tidal channel in an upturned car of which he was the driver. “I was responsible,” Kennedy admits, though one is not certain what he means by this. The crash “haunts me every day of my life”. He gives a surprisingly extensive version of Chappaquiddick, and of course the book would have been largely dismissed had he not done so.

Kennedy has no new facts to offer and his account, while emotionally frank in some ways (“Even though I was dazed from my concussion, exhaustion, shock and panic, I was rational enough to understand that the accident would be devastating to my family”), only revives all one's latent scepticism. And even the frankness has its limits. There is no hint here of the fact that Kennedy spent considerable time in the hours after the crash attempting to establish a false alibi for himself and to shift the responsibility to a family retainer - an action which in some ways was more revealing and less forgivable than even the crash itself.

Ted Kennedy was a youngest son whom time and tragedy turned into a patriarch. The descriptions of his early years remind us how very much he was the little boy in the family, 17 years younger than Joe Jr, 15 behind Jack, seven behind Bobby, to whom he was inevitably closest in adult life, but not as close as he was to his sister Jean - they even ate at a separate table from the rest of the family. But the key figure in his childhood was his father, adored but distant. Perhaps revealingly, the book begins with a rhapsodic description of early morning childhood horse rides with Joe Kennedy on Cape Cod. Equally revealingly, Ted still remembered word-for-word 65 years later what Joe told him in the 1940s “If you decide to have a non-serious life, I won't have much time for you.”

At Harvard he cheated in his Spanish exams, was sent down - again it is his father's reprimand that he remembers - and joined the army. By 1958, married to Joan, he is swept along in Jack's presidential bid and learns how to work a crowd. Then, aged 28, he is suddenly brother to the president. In 1962, opting for the serious life, Ted wins a bitter election in his home state, Massachusetts, and takes the Senate seat he was to occupy for the next 47 years.

With JFK's assassination 12 months later, though, the glittering prize became a fateful burden, and doubly so for Ted when Bobby was shot dead in 1968. Kennedy writes with moving simplicity about the long nighttime sailing trips he made that summer, often alone, always thinking about his brother. His speech at Bobby's funeral mass was perhaps the best he ever made, a mini-manifesto for the rest of his career.

That career, after Chappaquiddick, was never going to end in the White House. There were personally troubled years in the 1980s. The Rabelaisian streak almost got the better of him again. His first marriage collapsed. His nephew William Smith, out drinking with Kennedy, was accused of rape - the book skates over the case. In politics, though, Kennedy stuck with it, on health reform above all, but also Northern Ireland, arms control, schools and minority rights. He became the biggest figure in US domestic politics - sometimes in more senses than one. By the end he had earned the right to adopt the self-important tone that becomes a bit wearisome in his prose.

Those of us who saw his last big public speech at the Democratic convention in Denver a year ago were right to be moved by it, especially when we read his harrowing account of what a touch and go appearance it was. Sticking with it is Kennedy's chosen theme in this book. It is why, in the end, this frequently irresponsible and self-indulgent man has gone to the grave with a justified reputation for seriousness, principle and hard work.—Dawn/The Guardian News Service