This book is part of the Canonsgate Myths series, in which modern authors rewrite ancient myths and legends. I've read a couple of the others in the series including Margaret Atwood's take on Odysseus's return to Ithaca and his dealings with Penelope's suitors and her maids.
But to ask well-known atheist, Philip Pullman to rewrite the Christian gospels was an interesting decision. His premise is that Mary gave birth to twins; one called Jesus, the other called Christ. Jesus is a revolutionary who inspires people to follow him. Christ stays in the background and records what is happening for posterity.
Pullman uses this book to attack the hypocrisy of the Roman Catholic Church and its protection of pedophile priests, and those who start wars and persecute people in the name of religion.
"And from time to time, to distract the people from their miseries and fire them with anger against someone else, the governors of this church will declare that such-and-such a nation or such-and-such a people is evil and ought to be destroyed, and they'll gather great armies and set off to kill and burn and loot and rape and plunder, and they'll raise their standard over the smoking ruins of what was once a fair and prosperous land and declare that God's Kingdom is so much the larger and more magnificent as a result."
Powerful and thought-provoking for believers and atheists alike.