From the inside flap:
"This bone-chilling novel, in which a medieval devil speaks directly to his reader -- his tone murderous one moment, seductive the next -- is a never-before-published memoir allegedly penned in the year 1438. The demon has embedded himself in the very words of this tale of terror, turning the book itself into a dangerous object, laced with menace only too ready to break free and exert its power..."
C.S. Lewis's The Screwtape Letters plus Voltaire's Candide equals Mister B. Gone.
The story: a minor demon, Jakabok Botch, born in a Ninth Circle ghetto, is fished blindly out of Hell by human demon hunters. Botch (aka, Mister B.) is rescued from them by Quitoon Pathea (aka, Mister Q) , a high-born and gentlemanly (by infernal standards) demon, who becomes Botch's traveling companion for many years.
Pathea's strange obsession with new human inventions becomes understandable when, arriving in the town of Mainz, he and Botch interrupt a divine bloodbath, and an equally divine conspiracy...
Readers seeking the gore-iffic brilliance of Barker's early works or the dark beauty of his later works should skip this one. It's a lightweight YA-level read, with fleeting mentions of torture (this is set during Medieval times), and (intentionally) half-hearted threats from a demon-book who can't make deliver on them, given his circumstances.
That's not to say this isn't a good read; it is. It's simply not one of Barker's better novels. While it's certainly adroit, humorous and moves along at a clipped pace, it has no real twist to speak of -- something that might've made this as landmark as Lewis's The Screwtape Letters.
Worth your time, if you don't expect much. Better Barker thrills: his three-volume anthology Books of Blood, The Great and Secret Show, The Hellbound Heart (this novella is the basis for the Hellraiser films), Sacrament, Galilee, and, what I consider his masterwork, Imajica.