We live in an age of instantcelebrity and frenetic branding. Companies repeatedly re-brand and change their logos, often at great expense and frequently to no good effect. The Holy Grail is to achieveenduring and immediate recognizability. The ultimateaspiration is to match the Coca-Cola logo (invented in 1886) and bottle (designed in 1915), or to emulate the more recent golden 'M' of MacDonald's (1968) and the 'swoosh' of Nike (1971).

In my recent book, 'Christ to Coke. How Image Becomes Icon', I look at 11 representative images from art, politics, the commercial world and science that have achieved the highest level of iconic status. Is there a magic formula for branders? If I could I would keep it secret, and sell my services very very expensively! But there is no sure-fire formula; no fixed set of characteristics that ensure success. However, we can learn varied and complex lessons from the extraordinary life stories of mega-successful images.

1. What is an iconic image? Iconic images transcend time, place and even original function.

'Iconic' is now a much over-used word. Somebody who is passingly famous is described as iconic. The images with which I am concerned are more than just very famous. They have an astonishing degree of universal recognition, taking on diverse meanings as they are transmitted across cultures. The most indelible of them act as cult objects.

The earliest icons were generated to serve religious devotion. Eikon, the Greek word for image, entered modern currency as the name for the authorized images of Christ and the saints in Orthodox Christianity. This devotional aspect persists in many later icons. In the 'posterized' portrait by Jim Fitzpatrick, Che Guevara has been transformed over the years from a Soviet-style Communist revolutionary into a saintly martyr for idealistic youth.

Rulers and dominant entities typically go to great lengths to establish an authoritative image, redolent of their supreme power and ubiquitous presence. Sometimes a symbolic proxy does the job, like the regal lion, which was adopted by MGM as the snarling emblem of their Hollywood kingdom.

Even the icons of modern science, DNA and E=mc², have acquired a quasi-religious dimension, as arcane formulations intoned by the high priests of genetics and physics. The more science itself becomes inaccessible to most of us, the more the status of the priesthood is enhanced. The older Einstein, with his halo of wild white hair, plays the role of prophet superbly.

The 'rules' that apply to each type are somewhat different. The Coke bottle obviously does not work in the same way as Nick Ut's harrowing photograph of the napalmed girl fleeing in heat-seared agony along Route 1 in Vietnam. Oddly, a photograph can achieve the highest fame without our ever knowing name of the author.

The Mona Lisa would hardly have reached its dominant position amongst iconic paintings independently of its artist's name. Would Dan Brown's book