Guy Gavriel Kay's tales of kingdoms and empires that never quite were blend real history with an economic use of magic; blink and you would almost miss the interventions of the supernatural. Lord of Emperorsis the second half of his The Sarantium Mosaic, a full-blooded and passionate epic of Byzantine intrigue and artistic commitment. All of his characters are in the great city of Sarantium now--Crispin, the great mosaicist, Gisel, the exiled queen of the barbarian kingdom of the West and Rustem, the brilliant young doctor and unwilling spy. Emperor Valerius and his wife Alixena have plans for their world--they are summoning troops from all directions--and plans for their city. Crispin is working on the dome of the great temple; and yet time and chance, those rulers that lie beyond all emperors, will ultimately dispose of all plans and all planners. Kay is as good on the manners of charioteers--there is a particularly fine chariot race here--as he is on the double-crossings of generals and imperial secretaries. This is a rich complex fantasy with a real sense of how its world works. --Roz Kaveney