Although Michael Moorcock is so prolific that I can't claim to have read even a tenth of his work, the works I've read have been those dealing with time travel ("The Dancers at the End of Time" series) and alternate realities (The "Oswald Bastable" series). "Behold the Man" is a time travel story, to be sure, but it transcends that conceit to become a fractured reflection on the nature of belief and on the history of Christianity.
Karl Glogauer is a complex and deeply troubled former psychology student with a strong interest in both Jung and Christianity. Glogauer has been degraded by the world and yet is still a brilliant and independent thinker. He is full of self-loathing, so much so that his self shifts almost completely (and at times uncontrollably) to please those around him. He is obsessed with Christianity intellectually, emotionally, and even sexually.
At a point of crisis in his personal life, he is given the opportunity to go back in time. He wants to witness the crucifixion, to see just how much of the New Testament is history and how much is myth (in other words, how much of the New Testament is scripture, truth that comes from God and how much is doctrine, the imperfect interpretation imposed by man). Instead of simply observing and having his questions answered, Glogauer finds that history is not as recorded in the Bible. Ultimately, he decides to correct the discrepancies, to build up the myth of Christ by taking on the role himself.
On the surface, the plot reminded me of the excellent (but very different) "Past Watch" by Orson Scott Card, in which time travelers correct the brutality that followed Columbus' discovery of the new world. "Past Watch" was an intellectual work, a reimagining of society. However well rendered, the characters of history were ultimately pawns to be repositioned to change the outcome of the game.
"Behold the Man" is about belief instead. Robbed of comfort of the supposed historical truth of the Bible, Glogauer sets out to ensure that future Christians will not have to face a similar dilemma. Far from being a selfless martyr, he does this in part because his own obsessions require him to do so. Sacrificing himself for the world becomes on some level a selfish act, one of the many astonishing contradictions in his character.
This is a brilliant and outstandingly complex book, but perhaps not for everyone. Numerous and compound blasphemies and heresies fill the work. The last paragraphs are reminiscent of the Jefferson Bible (which removed all references to Christ's miracles), and are a final narrative rebuttal of the story of the Gospels.
This book will probably only appeal to the type of reader who can see the brilliance (and perhaps even humor) of a story like Three Versions of Judas by Jorge Luis Borges, in which a theologian convinces himself through tortured logic that Christ was in fact Judas. I would love to hear from anyone else who has also read the book, as there is much to discuss.