David Rollo's volume contains reliable and highly readable English translations of two medieval Latin texts that testify to the growing concern with male-male sexual behavior in clerical circles as well as to the process whereby churchmen of the High Middle Ages singled out sodomy as unnatural, thus making of it an especially monstrous sin rather than one delict among many that, say, the earlier penitentials described and prescribed penances for. The two texts could not be more different. Peter Damian's Liber Gomorrhianus (The book of Gomorrah) was in fact an epistle the prior of the monastery of Fonte Avellana addressed to Pope Leo ix (1049–54) to which its colourful title was later attached. Peter demands that sexual acts between males be uniformly and severely penalised, lumping solitary masturbation with anal and intercrural intercourse and mutual masturbation. Above all, no man guilty of any form of this sin should enter or remain in holy orders, contrary to what Peter has frequently observed to be the case, to his consternation and voluble indignation. Pope Leo's response is extant (and translated by Rollo); while in general agreement, he would allow those who repented of their past actions and abstained to retain their positions. Alain de Lille's De planctu naturae (The plaint of nature), dating most likely from the 1160s, belongs to the genre of high medieval Platonizing allegories. In form it is a Menippean satire, alternating sections of prose and verse (which Rollo renders as prose), of which the most famous example is Boethius’ Consolation of philosophy. As Philosophy appears to Boethius, so Nature appears to Alain, but there resemblance ceases. Nature is joined by a pageant of mythological and allegorical figures. Alain's style is extravagant in the extreme, the text chock-a-block with rhetorical figures and wordplay of every description often to the point of impenetrability. The speaker, in the poem with which the work begins, is incensed that men are having sex with other men: rather than make use of their ‘hammers’ they themselves become ‘anvils’, hermaphrodising themselves – Alain coins the verb ‘hermaphroditare’ (p. 104). While this outrages Nature, too, she is also exercised about heterosexual delicts and sundry other sins that are catalogued at length and with copious mythological references. Rollo's translations are based on the standard critical editions – Kurt Reindel for Peter, Nikolaus Häring for Alain; in his notes he explains his rationale for preferring a manuscript variant or a particular rendering, generously crediting previous translators (for example, James Sheridan) or interpreters (for example, Winthrop Wetherbee). The translations are sound; abundant notes explain the classical references; the introductions preceding the two translations contextualise them, that to Alain going some distance towards explaining his puzzles, ambiguities and seeming self-contradictions. Rollo points readers to secondary literature that can offer further elucidation. Production is almost perfect: on p. 57, line 3: ‘if’ should be ‘is’.