In LA the poetry business surges into mega hype, while back in London a screenwriter peddles his scripts round dingy, unheeding offices and cafes. In "Straight Fiction" it's a gay world where literature has been appropriately rewritten and cool is Hot. Over his marjoram ravioli, Cleve ponders "how Fanny Price made time with Mary Crawford, exactly how Frank Churchill strapped on Mr Knightly". Amid the horrors of a young mother's kitchen, "a field hospital of pots, pails, acids, carbolics and cauldrons of boiling laundry", he can imagine "having his legs amputated in here.

But no cooking ..." Both these conceits are presented with glacial wit, with flawless dialogue and gleeful detail, but the jokes go on too long In fact most of these stories go on too long There is an exception. "What Happened to Me On My Holiday" is beautifully constructed and infused with a rare, astonishing warmth and tenderness. But Amis chooses to disguise these archaic qualities by writing in a ghastly phonetic speak: "Doo many vields, doo many drees, doo muj zand, doo muj zee." This does your head in. Despite a few devastating phrases, some brilliant exchanges of dialogue and two moments of real humour, this collection really scrapes the bottom of its barrel. To quote gay Kico: "I see that, I'm like, let me out of here." Or it's Hot to be prim.. The problem with the Kennedys is that everything significant has already been said about them, and the territory that remains is too dangerous to explore: reputedly Nigel Hamilton will never complete his biography of JFK after receiving a warning from the guys with pinkie rings. One's first response to David Heymann is to admire his courage, for he names names with wild abandon.

Cutting through all the nonsense about Lee Harvey Oswald as lone gunman - a proposition that can no longer be seriously upheld after ex-president Ford's 1995 revelation of the unpublished CIA and FBI material on the assassination - he not only targets the Mafia as the killers but fingers the Mob masterminds behind the events of 22 November 1963 in Dallas: Carlos Marcello and Johnny Roselli. Heymann is an assiduous researcher who has read all the relevant material and interviewed hundreds of eyewitnesses to the 42-year life of Robert Kennedy. As was made clear in Jeff Shesol's masterly study of RFK and LBJ last year - and indeed is obvious from the most casual reading - Bobby Kennedy was not a pleasant individual. Ruthless, arrogant, narcissistic: Bobby self-confessedly put the interests of the Kennedy family above those of the nation.

He suffered from a double handicap: like all the Kennedy boys he was overwhelmed by the dark figure of his monstrous father, the loathsome, bullying, fascistic, anti-semitic womaniser "Ambassador" Joe Kennedy, the man who backed Hitler to beat Churchill; and he was in thrall to his elder brother Jack, to whom he gave years of devoted service. When JFK was assassinated, Bobby was bereft: not only had he lost a beloved sibling but he was now on his own, for he could not rely on Teddy to do for him what he had done for Jack. Heymann gives Bobby credit for his achievements. As US Attorney-General in 1960-64, he probably accomplished more than any other holder of that office, even if his initial appointment was barefaced nepotism. His relentless pursuit of the Mob was one factor in the Mafia decision to "take out" the president; another was JFK's ingratitude at the role played by the Syndicate in helping to secure him the narrowly won presidential victory over Nixon in 1960. And after 1964, Bobby, who began life on the Right as Senator McCarthy's assistant, moved ever leftward, building a radical coalition of blacks, Hispanics and mainstream Democrats that might have taken him to the White House in November 1968.In the course of his spectacular career, Bobby made scores of enemies as much by his abrasive personality as his ruthlessness, but three were especially significant: LBJ, FBI director J Edgar Hoover, and Jimmy Hoffa of the Teamsters This argues for his inadequacy as a politician. No sensible operator would have alienated three such powerful figures simultaneously.

Bobby effectively destroyed the credibility of Hoover and his G-Men by demonstrating the power of organised crime, whose existence Hoover had always denied; in the early 1960s, Hoover had 600 agents assigned to the "Communist threat" and only six to the Mob. Bobby then succeeded in redoubling Hoover's hatred by his friendship with Martin Luther King, whom the Bureau director detested with an insane loathing, mainly based on King's frequent liaisons with a bevy of white liberal groupies. It has to be conceded that King scarcely emerges from this account with credit. He described one of his white mistresses as "a piece of tail who can go all night long".Martin Luther King was a fabled womaniser, but his trysts fade into insignificance alongside the priapic antics of the Kennedys. Heymann, whose previous subjects include Liz Taylor and Jackie Kennedy, really hits his stride when he enters Kitty Kelley territory and we finally realise what "a candid biography" truly means.