Sphinxlike organ retains its mystique

The best scientific sagas have a pot of gold at the end. A famous example is James Watson's The Double Helix , where the pot is the structure of DNA.

Carolyn Abraham has a saga to tell, but there is no pot of gold, just a glimmer in the sand.

On his death in 1955, Einstein's brain was removed by Thomas Harvey, the pathologist doing the postmortem. This book is about what he did with the brain, which remained in his possession for the next 41 years.

First, there is the question of whether Harvey was authorised to take the brain. Einstein seems to have agreed that his brain should be examined, but not to publication of the results. But Einstein, the iconic scientist, must have known that without publication, knowledge is worthless.

Then there is the saga of Harvey himself. Much of the book is a vivid and touching account of how possession of this unique organ came to dominate his life, itself a story of tragedy, indecision and impulsive behaviour.

Harvey, untrained as a research neuroscientist, had two obsessions: that the brain would reveal the secrets of genius, and that it would make him famous. Neither happened. But the brain carried with it the charisma of Einstein himself, so that everyone who saw it was galvanised by thoughts of wealth or glory. Scientists, journalists, entrepreneurs, Einstein's executors - all tried to grab a piece of the action.

But what was the action? To sell bits of the brain as souvenirs? To own a relic? To unravel the reason why Einstein was Einstein? So the book is about the unending, if intermittent, quest by Harvey to find someone to unlock the secrets of Einstein's brain. But what secrets, and, if we knew them, then what? Various people interviewed by Abraham express similar doubts.

That did not stop Harvey, by now clinging to the brain like a child to a favourite blanket. Impulsive in the extreme, first he prevented serious study of the brain, then erratically either sought expert help or prevented access. Of course, really there was no serious scientific question to be answered. We still do not know why John can play the flute better than Jim, never mind what makes a Bach, or why Jill can understand differential equations, whereas Susan thinks them gibberish, let alone how Einstein's brain can derive E=mc2. We do not even know what to look for, though collections of brains from exceptional people have been studied for decades.

The only reported research on Einstein's brain is that by Sandra Witelson, who found that part of Einstein's brain - the bit that, among other things, is important for mathematical ability - is larger than that in a collection of other brains. But is this truly responsible for his gifts and how does increased size affect processing power?

Abraham gives us a truly amazing saga with wit and style, though she tends to recreate conversations and thoughts that, though plausible, are largely imaginary. For example, there is a description of Einstein's postmortem examination that you should certainly not read over your breakfast.

In his late eighties, Harvey finally returned what bits he had to their original lab in Princeton. They are there still, I suppose.

Joe Herbert is professor of neuroscience, Cambridge University.