We nipped along the the Southbank Centre last night to catch author and neuroscientist David Eagleman in conversation with Philip Pullman, featuring readings from Eagleman's rather brilliant book Sum.

The book is a series of forty hugely imaginative vignettes that explore what the afterlife might be like. Eagleman explained to the audience that he's a Possibilian, neither religious nor atheist, but actively engaged in the vast space of 'what if...' between the two.

The event featured recorded readings by Nick Cave and Stephen Fry, as well as live readings by Miranda Richardson and Jarvis Cocker: not a bad cast of narrators to have for your book.

We were given a copy of the paperback version of the book, published by Canongate Books, and designed by Angus Hyland at Pentagram. The cover features gatefold flaps, with the gap in the doorway die-cut to reveal a yellow highlight. (Something about the look of the book reminded us of the Pocket Canons that Hyland also designed, in 2001, one of which featured an introduction by the aforementioned Nick Cave, whose latest book, The Death of Bunny Munro, is available as an iPhone app from Enhanced Editions, who are also publishing a digital version of Sum.)

Checking out Eagleman's book this morning, we were interested to see how many different versions of the cover have been produced in a relatively short space of time (the book having been first published in February of this year).

Of the series above, from left to right are: the hardcover version from Pantheon; then a revised version, also from Pantheon; the Pentagram paperback from Canongate; a revised (more populist?) paperback from Canongate due out in April next year; and the Norwegian version. Vintage look to have a paperback version coming out too, in January next year.

In a piece for the Wall Street Journal by Jeffrey Trachtenberg, Patricia Johnson from Pantheon explained why they redesigned their cover:

"Our original cover on 'SUM' was too otherworldly. We think this book has the potential to be a perennial. Why not go to our accounts and say, 'We think we put the wrong jacket on it, will you bring it in again with a new feedback?' " (via Galleycat)

Philip Pullman touched on the fact that the book didn't sit happily in any particular publishing category, and it seems that the book's publishers are finding it tricky to find the right look for it.

Here's an excerpt from Sum, a tale called Descent of the Species:

"In the afterlife, you are treated to a generous opportunity: you can choose whatever you would like to be in the next life. Would you like to be a member of the opposite sex? Born into royalty? A philosopher with bottomless profundity? A soldier facing triumphant battles?

But perhaps you've just returned here from a hard life. Perhaps you were tortured by the enormity of the decisions and responsibilities that surrounded you, and now there's only one thing you yearn for: simplicity. That's permissible. So for the next round, you choose to be a horse. You covet the bliss of that simple life: afternoons of grazing in grassy fields, the handsome angles of your skeleton and the prominence of your muscles, the peace of the slow-flicking tail or the steam rifling through your nostrils as you lope across snow-blanketed plains.

You announce your decision. Incantations are muttered, a wand is waved, and your body begins to metamorphose into a horse. Your muscles start to bulge; a mat of strong hair erupts to cover you like a comfortable blanket in winter. The thickening and lengthening of your neck immediately feels normal as it comes about. Your carotid arteries grow in diameter, your fingers blend hoofward, your knees stiffen, your hips strengthen, and meanwhile, as your skull lengthens into its new shape, your brain races in its changes: your cortex retreats as your cerebellum grows, the homunculus melts man to horse, neurons redirect, synapses unplug and replug on their way to equestrian patterns, and your dream of understanding what it is like to be a horse gallops toward you from the distance. Your concern about human affairs begins to slip away, your cynicism about human behavior melts, and even your human way of thinking begins to drift away from you.

Suddenly, for just a moment, you are aware of the problem you overlooked. The more you become a horse, the more you forget the original wish. You forget what it was like to be a human wondering what it was like to be a horse.

This moment of lucidity does not last long. But it serves as the punishment for your sins, a Promethean entrails-pecking moment, crouching half-horse halfman, with the knowledge that you cannot appreciate the destination without knowing the starting point; you cannot revel in the simplicity unless you remember the alternatives. And that's not the worst of your revelation. You realize that the next time you return here, with your thick horse brain, you won't have the capacity to ask to become a human again. You won't understand what a human is. Your choice to slide down the intelligence ladder is irreversible. And just before you lose your final human faculties, you painfully ponder what magnificent extraterrestrial creature, enthralled with the idea of finding a simpler life, chose in the last round to become a human."

Excerpted from SUM: Forty Tales from the Afterlives by David Eagleman copyright © 2008 by David Eagleman. Reprinted with permission by Pantheon Books, a division of Random House, Inc. All rights reserved.

Listen to Eagleman discussing the book in this NPR interview.