A man of many contradictions and, as we have discovered, sexual peccadillos, he was more than just a president to most Americans - he was the idealised representation of what they wanted themselves, and their country, to be.

He was young, he was progressive, he was seen as being liberal and supported the civil rights movement (although he never impressed Martin Luther King) and, crucially, he was seen to be the man prepared to stare down the Evil Empire at the height of the Cold War. In short, for many Americans, he was America.

So the date of November 22, 1963, is one that is emblazoned on people's minds. To borrow from another American president, it is a date that will live in infamy.

Lee Harvey Oswald's assassination of Kennedy that day in Dallas almost broke America, causing paranoia and a national crisis of confidence that some social historians claim was never fully regained. So it is only fitting that America's most iconic author should turn his considerable attention to America's most iconic president.

King has always seemed fascinated by the Americana of the 1950s, a time and place he visits frequently in his work. Here he returns once again with the story of high school teacher Jake Epping who makes an astonishing discovery - the storeroom in his dilapidated local diner is also a portal back to 1958. He's a lonely divorcee with few ties to his community.

One of the few friends he has is the diner's owner who is terminally ill; he has a proposition for his younger friend - would he be prepared to travel back in time and prevent the assassination of JFK?

The author will probably argue that the book is as long as it is because he wanted to properly evoke the era, and there is no denying there are times where you feel like you could be in 1958. But frankly, there is too much evocation and not enough action.

As he gently ambles on his new life in Texas, the reader is tempted to shout . . . just get on with it.

After all 'what-if' fiction has produced some cracking reads in recent years and the idea of an America where Kennedy is never shot is a fascinating one.

We eventually get to the good stuff, but by that stage it seems almost perfunctory and the wrap-up is too quick and premature.

An entertaining read but those of us who devour King's books will feel that it could have done with some judicious editing and got to the point a lot quicker.