Not long after he became the leader of the free world in 1961, John F Kennedy started musing about a book he would one day co-write with his younger brother and advisor, Robert. It would be titled, they both imagined, The Poison of the Presidency. JFK - taking office at an unripe age of 43 and inheriting the cold war from his predecessor just as it started getting hot - had few reasons to like the job. He met with a policy disaster barely three months into his term. It was, of course, the Bay of Pigs - a spectacularly mismanaged covert attempt to invade Cuba and overthrow Fidel Castro, which floundered in 72 hours. When Kennedy heard of the humiliating fiasco, he broke down. "He came to the White House to his bedroom and started to cry... put his head in his hands and sort of wept, " Jackie, JFK's wife, told an interviewer long after.

Fast forward another two decades to 1989 and we have in front of us George H W Bush all braced up just as his forces prepare to invade Manuel Noriega's Panama. He remembered that on the night before he had laid in bed 'unable to move his neck or arms. ' "The tension had taken hold. The responsibility for those lives, even though I had been in combat myself, " he later recalled.

This is recorded history, and yet such images mostly tend to be forgotten. Historical moments such as these are relegated to the margins of public memory by the myth of power. All too often, we tend to think of our leaders as heroes, or indeed, villains - the really powerful figure always above or below that human median. And one of the refreshing things about The Presidents Club - which recounts many such scenes as are mentioned above - is that the book tries to explore that very median, those very margins of power where the wretched and bungling human once again begins to show, weeping with his head in his hands.

Co-written by Time magazine editors Nancy Gibbs and Michael Duffy, this new book is a short historical study of all the post-war US presidents - Harry Truman onwards - and shows how the living predecessors collaborated with the incumbent. How they cut across party lines and rose above political rivalries, to support and 'protect the presidency. ' With Truman reaching out to his depression-era precursor Herbert Hoover - "the most hated man in America, his motorcades [were] pelted with rotten fruit" - to help resolve the European food crisis, the Presidents Club first found its modern form. And ever since, the tradition has been handed by every generation up until the present day, with Bush Jr telling Barack Obama in 2010, "the office transcends the individual. "

The book frequently and variously refers to the club as a 'trade union, ' a 'secret society, ' a 'family' and a 'fraternity. ' But the so-called club is not quite an inner-cabal, and there are no blood rituals or Masonic handshakes to be seen. It is more of a concept, driven essentially by the need of the incumbent to glean as much professional advice as possible from his seniors, and the desire of the precursors to get right back in the game. "There is a lure in power, " Truman wrote during the final days of his presidency, "just like gambling and lust for money. "

The book's focal points are strewn throughout the post-war American history. The narrative goes jouncing all the way from the Korean war to the Vietnam war;from the Pentagon Papers to the Watergate scandal;from the old Arab war to the new one. And the spotlight is always on the commander-in-chief and his rapport with his precursors at a given moment of historical relevance. But The Presidents Club, when seen only as a work restricted to its theme, loses much of its value. There's just so much more happening in the current book apart from the club dynamics and the political back-channels of the White House that it attempts to examine.

It is said that political theatre acquires much more colour behind the proscenium, and The Presidents Club is worth a read solely for the amount of backstage presidential trivia it offers. Consider President Clinton being taught how to salute properly by the ex-president and ex-army guy Ronald Reagan: "Bring the hand up slowly, as if dripping with honey, and then shake it off briskly, as if it were covered with something less pleasant. "

The Presidents Club is as meticulously researched - over 70 pages of end-notes and bibliography - as it is well-written. But what stays with the reader is the book's underlying assertion that power, apart from its corrupting and intoxicating effects, also chastens. And what better way to understand that than by looking at some of the lives of the front-men of the most powerful country in the world, who alone have experienced "the unique loneliness of being the most public man on the planet. "