The face and figure of Albert Einstein must be among the most recognisable on the planet. The pot-belly, the twinkling eyes, the frizzy white hair - for it’s the older Einstein that is known, fewer would recognise the trim 26-year-old who invented the theory of relativity - the moustache, and the deeply deeply lined face all signify one man, one European accent, and one equation, the inevitable E = mc2.

Inability to understand relativity, an almost universal human trait, is no barrier to recognition. Einstein is known, admired, revered, even loved by many who don’t have a clue about the real meaning of his theory, or even his ubiquitous equation. For almost three generations Einstein has been more than an honoured scientist and public figure; he has been a symbol of science, an icon, almost a talisman.

But now, in an age of scientific popularisation, public understanding, lifelong learning and the free flow of electronic info-bits, Einstein is taking on a new lease of life. Increasingly, it seems, Einstein is not just the creator of relativity and the photon model of light; not only the genius who explained gravity in terms of curved space-time and cast doubt on the correctness of quantum theory; he has become everybody’s favourite explicator of those subjects, and of all else that is scientific, or simply “intellectual”.

Rather like Virgil leading Dante through the inferno, Einstein is now used to guide all of us through warped space-time, around black holes and into the strange purgatory of the quantum microworld.

Where science is being explained, particularly cosmic science, and especially when the target audience is expected to know little about the subject, the mantra “Einstein” is soon heard and Einstein the guide is close behind.

In the witty and well-written Scrooge’s Cryptic Carol: Three visions of energy, time and quantum reality by the Bristol-based physicist, writer and illustrator Robert Gilmore, Einstein appears as the ever-changing Spirit of Time who conducts young Scrooge on a whistle-stop tour of relativity.

At the other end of time, in Lawrence M Krauss’s new book, The Physics of Star Trek, the friendly authorial voice of Krauss himself does the guiding, but Einstein puts in an early appearance, as the eleventh word of Stephen Hawking’s preface. Little wonder then, that in the 26th century, when the Starship Enterprise’s Commander Data has his IQ boosted to 1,200, it is to a re-creation of Einstein that he turns for a worthwhile discussion of the appropriate number of dimensions in which to unify the whole of fundamental physics.

Einstein was born in the year that Edison patented his incandescent light bulb, 1879; three years after Custer’s last stand and six years before Carl Benz installed the first gasoline-burning internal combustion engine in a motor car. Yet the passage of time and the development of technology have done nothing to dim the brightness of Einstein as a guiding light. On the Internet you can now go Surf’in with Einstein (http:www.lni.netricksurfweb. html) as well as exploring The Ultimate Einstein CD-Rom or consulting Einstein Online.

Einstein’s fame is not a mystery, but his ability to capture and hold the public heart is a remarkable and dynamic phenomenon. As he said himself, “Why is it that nobody understands me and everybody likes me?” And, we might add, why is it that this continues to be the case more than 40 years after his death?

The lack of understanding of Einstein is easy to explain. Whatever Einstein thought of it, relativity is an intrinsically hard subject (and quantum theory even worse). The difficulties are not insurmountable; there are now excellent books at all levels, from popular to post-graduate, on every aspect of Einstein’s main creation, but none of them can be fully comprehended without some effort on the part of the reader.

Despite this, many readers are willing to accept the challenge and many find their efforts appropriately rewarded. Even those who are unsuccessful (and probably no professional relativist would claim to have been totally successful), have the enjoyable feeling that that they are grappling with a worthwhile mystery.

Explaining the almost instinctive liking that so many now seem to feel for Einstein, the ready willingness to trust him and go with him is a different matter. My own impression is that this is a much newer phenomenon. A decade or more ago, Einstein would certainly have been a symbol of brilliance, but the instinctive urge of many (most of whom seemed to want to write to me and other physicists about it at the time) was to overthrow Einstein, to beat him at his own game. Why is this less true now?

One factor may be the fuller picture of Einstein the man that we now possess. Following Einstein’s death in 1955, his loyal secretary, Helen Dukas, and his executor, Otto Nathan, undertook the guardianship of Einstein’s public image. Overly inquisitive investigators were steered away from grey areas of the great man’s life or simply denied access to certain material.

Now, after the almost complete opening of the Einstein papers (some letters relating to his relationship with his son are expected to remain private until well into the next century) and a good deal of scholarly ferreting, much of the Einstein enigma is being stripped away. Denis Brian’s immensely readable Einstein - A Life, the latest, and easily the best, in a progression of revealing biographies, gives a “warts and all” picture of Einstein, and a very human and sympathetic picture it is. The Einstein that emerges is far from being a monk-like sage, but he is appealing. Even the rebellious, know-it-all student Einstein, whom it would have been a pain to teach, might have been a delight to know. Such books, and the magazine articles and broadcasts they generate, keep Einstein, and an increasingly “one-of-us” Einstein at that, in the public mind.

Brian’s biography, with its short chapters and chatty style, is a welcome replacement for the excellent but now somewhat dated biography by Ronald Clark, which was often said to “read like a novel”. Brian avoids novelistic exaggeration, but in a tell-tale passage, he reveals a possible reason for Einstein’s status. Special relativity, Brian says, “reached beyond electricity, magnetism, matter and motion to the nature of light, space and time itself. ” He adds: “It even touched on the secret of creation.”

It’s that last, atypical, sentence that gives the game away. Here we see an Einstein who not only triumphs in extending science and thought into new realms, but who perhaps, more mystically, holds out the key to an understanding that is beyond human understanding. We glimpse not only the new Einstein so skilfully drawn in the biography, but also a new age Einstein. I find this development rather unattractive, and I am glad that Brian almost completely avoids it. Others, who share an interest in Einstein but not a love of science, might feel differently.

Having stressed the role of Einstein as “ordinary bloke” and “mystic sage”, it’s only right to remind ourselves that the broad appeal of Einstein must reside to some extent in his multi-faceted character. The centrality of physics to his life is beyond dispute, so we all know where he is coming from. But his many interests mean that we can all find him looking in our direction at least some of the time.

Einstein was interested in all the Ps; philosophy, politics, physics, pacifism and even philandering. The Einstein who once wanted nothing more than to teach philosophy is also the Einstein who was offered the presidency of Israel; the Einstein who, more than anyone else, finally established the existence of atoms, and the Einstein whose womanising seems to have at least partially wrecked both of his marriages.

In case this sounds too worldly, we must also remember yet another aspect of Einstein; his disregard for worldly things. He is marked out by his lack of any desire for great wealth, his deep enjoyment of music and sailing, and his unceasing delight in the world of ideas and the life of the mind. This, combined with his physical appearance, have helped to create the “Uncle Albert” image that has been so well cultivated in the hugely successful series of books by Russell Stannard.

In The Time and Space of Uncle Albert, Black Holes and Uncle Albert and Uncle Albert and the Quantum Quest, the wise figure of Uncle Albert assists his niece Gedanken in a variety of scientific investigations. More recently, in Letters to Uncle Albert, Stannard, a physics professor, lends Uncle Albert a hand in his mission to educate by answering some queries about science from young readers.

Stannard’s books are aimed at children, but they also appeal to grown-ups. In the “courteous translation” that Stannard provides of Einstein’s ideas, many adults have found the clarity of explanation they have long sought.

Ultimately, it is Einstein’s exceptionalism that keeps him in our minds. He was the one who created both special and general relativity. He was the one who incorporated gravity into the general theory, even when supposedly wiser heads warned him not to. And he was the one who dared to apply general relativity to the Universe as a whole in order to produce the first relativistic “model” of the cosmos.

Nonetheless, the steady release of information about Einstein’s life, and the ready availability of such an easily recognisable avuncular genius have undoubtedly helped to create the vogue for Einstein as a reliable guide through the difficult terrain of modern physics, and yonder to the Universe.

* Scrooge’s Cryptic Carol. By Robert Gilmore, Sigma Press, Pounds 9.95 The Physics of Star Trek. By Lawrence M Krauss, HarperCollins, Pounds 12.99 Einstein: A Life. By Denis Brian, Wiley, Pounds 18.99 The Time and Space of Uncle Albert (Pounds 3.99), Black Holes and Uncle Albert (Pounds 3.99), Uncle Albert and the Quantum Quest (Pounds 3.99), Letters to Uncle Albert (Pounds 4.99). By Russell Stannard, Faber and Faber Dr Robert Lambourne is a visiting fellow at Kellogg College, Oxford, where he is also the associate tutor in Physical Science in the Department for Continuing Education.