Michael Barber thinks that "one of the most devastating book reviews ever" is the one penned by John Gager for Hyam Maccoby's The Mythmaker: Paul and the Invention of Christianity. He cites a portion of it:
"Maccoby’s treatment reads like a (surely unintentional) summary of nineteenth century polemical-apologetic ‘scholarship’ of a liberal Christian variety: Jesus against Paul; Paul as the second (and real) founder of Christianity; Paul as the opponent and falsifier of Judaism; the predominance of influence from Hellenistic mystery cults on Pauline thought. Still, the book might have been redeemed with an ever so slight shift in its self-description. If, instead of representing it as a work of historical scholarship, the author had described it as a piece of historical romance. . . we might have been able to enjoy it as fiction." (JQR, 79/2-3 (1988-1989): 248 [248-250])Not a bad example. I think my favorite scathing critique is the New York Times review by the late Anthony Saldarini for Robert Eisenman's James the Brother of Jesus -- that lovely work of "scholarship" which portrays the Dead Sea Scrolls as Christian documents, with James the brother of Jesus standing in for the "Teacher of Righteousness". From the review:
"[Mr. Eisenman's] conclusions are improbable, his arguments incoherent and his prose impossible. Many chapters read like rough notes taken from a file drawer. Diverse themes are thrown together, topics are repeated without reason or cross-reference and arguments are left half-finished. The publisher's lack of editorial supervision is scandalous...Anyone else care to share a review which deserves a place in the Devastating Hall of Fame?
"In arguing [his] bizarre thesis, Mr. Eisenman ignores the normal canons of historical argument and of literary analysis. He treats later Christian sources, which contain legendary material, as historically reliable. Instead of critically assessing the biases of the so-called pseudo-Clementine literature from the third and fourth centuries, and of the first-century Acts of the Apostles, he declares Acts suspect because it is part of the canonical New Testament and judges the pseudo-Clementines as a repository of suppressed but reliable traditions...
"[Mr. Eisenman] displays little interest in modern critical scholarship on ancient Jewish and Christian history and documents, and he thus adopts less probable interpretations without arguing with his peers. He justifies himself as a maverick fighting the 'dominant scholarly consenses' from a position outside the 'traditional or received order'...
"Mr. Eisenman's interpretations are frequently inaccurate and biased... [The] dedication of his book to [Jesus son of Sapphias] is consistent with his irresponsible misrepresentation of the important and interesting history of the Jews and Christians of antiquity. They and we deserve better."