Or thirteenth, if you count "Out of the House of Life", which is primarily a spinoff novel about Madeline de Montalia (former lover and vampiric "childe" of Saint-Germain), but which does include some flashback scenes to some of Saint-Germain's early history. Or sixteenth, if you also count "A Flame in Byzantium", "Crusader's Torch", and "A Candle For d'Artagnan", the spinoff series about Atta Olivia Clemens, an earlier vampiric "childe". This book is, after a fashion, a sequel to "A Candle for d'Artagnan". The book is set in seventeenth century Rome, 30 years after Olivia's death, and somewhat more than that after "Mansions of Darkness". The plot and historical settings were interesting enough, if not Yarbro's best; the love interest, for a change, was neither traumatized, killed, nor psychotic, and even the secondary female character, who WAS traumatized and a bit difficult, was at least not completely psychotic. It was interesting to see, for a change, that the diligence of the church investigators actually worked to Saint-Germain's advantage. The only real problem with this book was that the writing was inexcusably sloppy. I've long since accepted the fact that there are going to be errors in any mass-market paperback, and in spite of the fact that we pay "quality paperback" prices for the current run of Saint-Germain books, they are basically mass-market paperbacks in Sunday-Go-To-Meeting clothes. And Yarbro has always tended to be a tad on the sloppy side about her proofreading, but I can accept a typo or three per book without getting all worked up over it. But if there aren't two dozen sloppy errors in this book (including one in which she misspells her own main character's name, as "Saint-German") (bottom line of page 363) I'll be astonished. Errors that an author of Ms. Yarbro's reputation shouldn't be making; things like "The courts have long preferred the claims of relatives over that of servants..." and "The worker have left for the night" and "there had been stalls for nearly a hundred horses here, and was thought a smallish enterprise" and "Now there were stall for twenty" (those last two being back-to-back) and "A few worldly slights such as mine must be seem more amusing than dangerous". This is far from a comprehensive list; these were all before page 75, and the frequency did NOT lessen as the book progressed. Get this woman an editor who isn't willing to rubber-stamp everything she writes because of her reputation. Someone capable of attention to detail.