The book in question is called The Good Man Jesus and the Scoundrel Christ, and it proposes that Mary -- the one you and I may sometimes call a Blessed Virgin -- gave birth to twin sons. One of these is Jesus, a charismatic teacher given to making the occasional over-the-top statements about leaving one's home and family to follow him. The other is Mary's favorite, to whom she gives the private pet name Christ. This, um, Christ makes it his business to write down the things that his brother says and does. Encouraged by a nameless Greek fellow, Christ takes ever greater liberties with the truth, turning more-or-less ordinary events (people sharing food so that everybody eats) into supernatural ones (a miraculous feeding).
We have not read the book, and yet Hitch's description seemed instantly familiar. Of course it did -- we had learned it all in seminary. (Or rather, since our own seminary prided itself on a neo-orthodox disposition, we learned there to dislike it.) This is the Gospel according to the Jesus Seminar. It is little more than story told by two centuries, and more, of theological liberalism. Heck, PBS even made the same point, with a series called "From Jesus to Christ." Get it? Cuz they're different.
Once you hypothesize an "historical Jesus" who can be distinguished from the Jesus described by Scripture, and start making claims about him which are not supported by Scripture, you arrive pretty quickly at the place where Pullman seems to be: believing that "a good man" has been betrayed by a cabal of priests and schemers who, for their own purposes, turned him into the Son of God. Pullman even claims that his character's logia are "much closer to what Jesus would have said." Closer, apparently, than the Bible.
Hitchens gets this, and sums it up quite nicely:
This is ... to raise the possibility that Christianity can be salvaged from itself, or at any rate from its later accretions, by a sort of “back to basics” revisionism. The difficulty that Pullman never quite confronts is that this involves ... an unmediated contact with the original message. Atheist though he is, Pullman turns out to be a Protestant atheist.
This is a clever turn of phrase, even if owes a debt to Leslie Wetherhead's "Christian Agnostic." Indeed, it seems pretty clear the Pullman and Wetherhead do drink from the same fonts, the difference being only in how they respond to what we may call, for lack of a less ugly phrase, "the liberalist hypothesis" concerning Jesus. One, concluding that the stories don't fit with a credible reality, concludes that they matter for other reasons; the second concludes that the whole thing has been a vicious sham which he will now unveil. (Paging Bart Ehrmann, as well as every other disappointed fundamentalist.)
Anyway, the review is modestly interesting, if only as further testimony to something we have long believed, which s that much (but not all) of the "New Atheism" is really just the howling of disappointed Christians. It has less to do with truth and falsehood than with their own emotions and experiences.