In theory, we should be looking for the things that make them special: magic and mystery among the Royal Family, wisdom and foresight among presidents and prime ministers. In fact, we want to feel that, underneath, they are just like us.
We expect the heroes of popular culture to be extraordinary people with extraordinary tastes, perhaps staying in bed all day, as John Lennon did, to promote world peace. But in our democratic age, we want a president, a prime minister or even a monarch to be what the Americans call a regular guy. So we were thrilled to learn that the Queen can make tea, that Bill Clinton went on camping holidays, and that the teenage Tony Blair wanted to be a rock singer.
Since the advent of mass democracy, all politicians have cultivated a public image. All that is new is the sophistication and thought that goes into the marketing. The aim is usually to make a political leader seem like the rest of us, but a bit more serious, conscientious and thoughtful: people should see him as the sort who might chair the school PTA or look after the cricket club finances. Excessively nerdish or highbrow tastes - for science fiction, say, or French philosophy -should be avoided, in Anglo-Saxon countries at least.
Between the world wars, Stanley Baldwin let it be known that, as he began a radio broadcast, he lit his pipe. Harold Macmillan was famed for reading Trollope's novels, confirming his image - in contrast to his predecessor, Anthony Eden, who had repeatedly lost his temper during the Suez crisis - as an unflappable, contemplative type.
Harold Wilson's predecessor was Sir Alec Douglas-Home, a scion of the aristocracy. So Wilson, originally an economics don, wanted us to know he put HP sauce on his food. Margaret Thatcher insisted, against all credulity, that she cooked breakfast for her family. President John F Kennedy was presented as a devoted family man with a taste for the arts. We know now that all he was really interested in was getting movie actresses into bed.
Often, the spin doctors' idea is to make that kind of correction to reality, or at least to popular beliefs about reality. That, presumably, is the point of publicising George Bush's reading list. Ronald Reagan could get away with a reputation for laziness in the 1980s. ("They say hard work never killed anybody. But I say: why take the chance?") But Americans are none too sure that, with the US economy and the war on terror in trouble, their president ought to be taking such extended holidays. Long, self-improving tomes about salt, flu and Alexander the Great are the sort of things a leader should read on vacation, they will feel: factual, down-to-earth and manly.
Sometimes, despite the spin doctors and marketing experts, an image goes badly wrong. John Major's revelations of visits to Little Chef restaurants confirmed what everybody suspected: that he was a bank clerk at heart. William Hague's baseball cap and 14 pints a night seemed contrived: everybody remembered him making a deeply serious speech to the Tory party conference in his teens. The Prince of Wales - talking to plants and meditating on the wisdom of Sir Laurens van der Post - is a disaster.
Mr Blair, however, has mostly got his image right. Enthusiasm for football and pop music and a touch of youthful rebellion go down well with the post-1945 baby boomers who form the backbone of his vote. Even the freebie holidays don't do much damage, because getting holiday bargains is a national preoccupation.
The Prime Minister is not much of a reader, we are led to understand, and the late Roy Jenkins did him a great service by describing his brain as second class. But he listens occasionally to a variety of modish thinkers, such as Anthony Giddens (the "third way" guru) and Amitai Etzioni (the American prophet of "communitarianism"). His wife, Cherie, with her New Age enthusiasms, is a bit of an embarrassment but a slightly eccentric, even naughty, spouse gives a prime minister the touch of colour that can't be permitted in his own image. Clement Attlee's wife was repeatedly convicted of motoring offences, Mary Wilson wrote poetry, and Denis Thatcher had notoriously right-wing opinions, bordering on racism.
Most of what we learn about our leaders contains a grain of truth, and probably much more. But it still gives a false picture. If you reach the top in politics, you aren't like other people. Your overriding preoccupation is with power - for that, you will sacrifice friends, family and principle - and the more of it you have, the less ordinary you become.
The suspicion has persisted that the US President's leisure reading does not extend much beyond the sports pages. That has now been revealed as the baseless denigration it surely is. Faithful to a ritual initiated by President John Kennedy, the White House has released a list of the three books Mr Bush has taken with him to Texas to read in whatever time is left from clearing brushwood and attending fundraising barbecues during his five-week break. And the intended message could not be clearer. Sports reading is not on the menu. This President is no blinkered simpleton, but a man fascinated by the great sweep of world history, and constantly on the lookout for ways to protect his country from the perils that beset it. The most striking choice is Alexander II: The Last Great Tsar by the Russian historian Edvard Radzinsky, which will not even come out in English until November.
But Mr Bush has pulled strings to get an advance copy of this biography of the reformer who liberated Russia's slaves in 1861, and was murdered by anarchists in 1881.
Next is Salt: A World History a 484-page tome by Mark Kurlansky, charting the history of what was once a vital strategic commodity. And if time is left, Mr Bush will tackle The Great Influenza: The Epic Story of the Deadliest Plague in History by John M Barry. The subject is the flu pandemic of 1918. Mr Bush has little recorded interest in this. But one presumes he wants to figure out how best to tackle any repeat, especially if terrorists use biological or chemical weapons.
It seemed an inspired choice for the first track in an election-winning selection on Desert Island Discs; a soulful ballad about a jobless man's pleas to his lover by a band no one had heard of. The appearance of Ezio, a Cambridge-based rock duo, on Tony Blair's playlist for the BBC Radio 4 show added a frisson of cool to the Labour leader's image in 1996, six months before he swept into Downing Street. But behind the playlist, which ranged from Debussy's "Clair de Lune" to Bruce Springsteen's "4th of July", others detected the cynical hand of spin. Westminster was alive with gossip that the list was a collaborative effort between Mr Blair and Alastair Campbell and Peter Mandelson. The more cynical suggested it was the work of Mr Mandelson himself, finely balanced to show the would-be prime minister's broad taste and aching hipness. A party spokesman fervently denied any dabbling in the dark arts by Mr Blair: "Every record was chosen by him. He knows more about music than anybody who works with or for him. He has been working on the choice for several weeks." The rest of the playlist was: "Cancel Today" by Ezio; "In My Life", The Beatles; "Adagio for Strings", Samuel Barber; "Cross Road Blues", Robert Johnson; "Wishing Well", Free, and "Recuerdos de la Alhambra", by Francisco Tarrega.
The Italian Prime Minister is the one politician who cannot be accused of leaking mere titbits about his private life to ensure his political progress.
With the Italian cruise-boat crooner turned prime minister, it seems no aspect of his existence, from plastic surgery to yoga, is not to be regarded as source of political capital. In such a torrent of gossip, allegations of selective spin are difficult to sustain.
Mr Berlusconi has equipped himself with a pet Neapolitan guitarist, Mariano Apicella, and on lazy summer mornings at his holiday home in Sardinia the two are to be found closeted working on new songs, for which the Prime Minister composes the lyrics.
Apicella has released an album of songs with lyrics written by Mr Berlusconi, including one entitled "How beautiful you are, nobody is more beautiful than you".
Mr Berlusconi claims to have great talent and taste in the matter of interior decoration.
It was said in one highly flattering biography that he and his wife Veronica, a former starlet, share a passion for paintings of the Venetian school, especially Tintoretto and Canaletto.
It is also claimed that every summer he gets together with his oldest friends for "spiritual exercises".
Mr Berlusconi himself describes the scene: "Wearing bermuda shorts we run, we read, we meditate and... we declaim the famous poems that we know by heart."
If you choose to believe the Kremlin spin doctors charged with shaping Vladimir Putin's image, the energetic 52-year-old rarely relaxes. Portrayed as a perpetual man of action and a leader capable of holding together the world's largest country, he is typically pictured practising a physical macho sport. His holidays, often taken in the Black Sea resort of Sochi, are short, low-profile affairs during which he receives other heads of state in his "rolled-up sleeves" mode. His leisure pursuits are clearly designed to strengthen his strongman image, to show the Russian people he is the right leader to deal with separatist rebels in Chechnya. Hence he is a lover of martial arts, be it judo, in which he is a black belt, or sambo, a Russian form of wrestling.
The bouffant-haired Japanese Prime Minister has never sought to hide the fact that in between trying to salvage his nation from a decade-long economic crisis, he is a fervent Elvis fan. Such is his passion for "the King" that Mr Koizumi helped raise money to raise a life-sized statue of the singer in Tokyo in 1985.
The politician, who also shares his birthday with Presley, has even gone so far as to introduce an album of his renditions of the crooner's classics, catchily entitled Junichiro Koizumi Presents My Favourite Elvis Songs. But while his interest may be genuine, the Japanese premier does not miss an opportunity to put his obsession to political use by ensnaring visiting celebrities in Elvis-oriented karaoke sessions.
After one session, a shell-shocked Tom Cruise said: "He's really an extraordinary man, and a pretty good singer. We sang Elvis together."
This year Mr Koizumi departed from his normal script to take Richard Gere for a twirl on a Tokyo dance floor.
For all his easy-going southern charm, Mr Clinton was just as anxious as the next American politician about the impact of his humdrum domestic choices on his poll ratings. Such was the former president's concern about where he should be seen to go on holiday in 1996, he commissioned his political strategist, Dick Morris, to conduct a poll of 10,000 Americans on a suitable destination. After it indicated swing voters like the outdoors, the White House decided Mr Clinton should don his walking boots. The result was a miserable week camping and hiking on the Snake River near the Grand Teton Mountains in Wyoming. Aides arranged a photo call with the First Lady rafting at the height of the Whitewater investigation into the couple's business affairs.
To his friends - and some colleagues - he is simply "Gerd", the lager-drinking Everyman who does not mind being photographed quaffing his favourite König Pilsener beer or supporting his local Hanover 96 side.
The German Chancellor, who is fighting for his political life in next month's general election, takes his "man of the people" credentials seriously. He shares a house in a middle-class suburb of Hanover with his wife and two adopted daughters, whom he sends to state schools.
In common with Tony Blair, he makes plain his desire to protect his children's privacy and bans the media from photographing them. But he has no problems with a candid shot that will help his election efforts.
The country's mass-circulation Bild newspaper showed photographs of the German leader patting a wizened river ferryman on the back, regaling locals while ensconced at a table in a Rhineland pub and chatting about his leather "garden slippers" to voters in one edition of the paper last week. Mr Schröder, a successful lawyer before his political career, also likes to point out that he was brought up in grinding poverty in the countryside outside Hanover after the Second World War.
Rumours suggest that the carefully crafted image is the work of his fourth and present wife, Doris Köpf, a former journalist on Bild.
The moment of amorous spontaneity when a curvaceous young woman planted a kiss on the lips of the heir to the British throne served to seal his status as one of the most eligible men of the 1970s. When Jane Priest, then 25, assailed the Prince as he emerged from the surf on Cottesloe beach in Perth, Australia, in 1979, the image swept around the world. Some 26 years later, Ms Priest confessed she was put up to it by press photographers. She said the Prince's entourage knew what was going to happen and she was even introduced to 29-year-old Charles the night before to make sure she was acceptable. But she admitted the Prince's flummoxed reaction was genuine: "I put my hands on his chest to give him a kiss and Charles said, 'No, I can't touch you, I can't touch you'."