A very interesting experiment and thank you for all your comments. Here on the blog, the initial votes weighed in for option two then started to swing back towards option one late in the day, whilst on Usenet's rec.arts.sf.composition the reverse happened.
Definitely a lot of interesting feedback and suggestions which I think I can summarize as:
Option One is the traditional approach - here's what the book is about without giving too much away. Some people liked it, some people found it dry and preferred the 'extract' version (Option Two)
Option Two brings the reader straight into the book but it doesn't tell the reader what the book's about. Some people like that, some people don't want any clues, they want to plunge straight in.
And some people didn't like either option. They'd prefer a hybrid or something completely different.
Moral: (besides you can't please everyone:) is that there's more than one way to read a book. Some readers don't bother with the back page at all. Some read the blurb, some the reviews, some go straight to the opening paras of the book.
So, I think I'll try an Option Three which is a revised Option One for the back page, and move the extract (Option Two) to the first inside page of the paperback.
So here it is, Option Three:
TWO PEOPLE, ONE MYSTERY, A BILLION WORLDS AT STAKE
Graham Smith is a 33 year-old office messenger. To the outside world he’s an obsessive-compulsive mute – weird but harmless. But to Graham Smith, it’s the world that’s weird. And far from harmless. He sees things others can’t . . . or won’t. He knows that roads can change course, people disappear, office blocks migrate across town. All at night when no one’s looking. The world’s an unstable place, still growing, sloughing off layers of reality like dead skin. One day you drive by, and it's changed.
Annalise Mercado hears voices, all from girls calling themselves Annalise. She thinks she's going crazy, until they tell her about Graham Smith, the men who want him dead, and how only she can save him.
So begins the story of two people whose lives appear fragmented across alternate realities. And how, together, they hold the key to the future of a billion planets. . . .
I've changed the tag line to push the mystery aspect of the book and revised the Annalise section. Resonance is a difficult book to describe without giving too much away - and part of its appeal is that just as the reader thinks they've worked out what's happening, they discover they haven't ... and when they do, there's an even bigger mystery behind that one.
So, I changed the Annalise section in an attempt to get away from the idea that Resonance is just a book about two weird people. There's a heavy mystery element. And Annalise is the driving force to finding a solution.