By Duncan Sprott

Knopf. 462 pp. $25.95

One comes across a wide variety of narrative voices in the course of reading fiction. But this is the first time I have opened a novel and found myself being addressed -- in fact berated as an ignoramus -- by a god. The narrator in Duncan Sprott's The Ptolemies is no less than Thoth, the Ibis God of the Egyptians, who in the realm of story is supreme, being God of Wisdom, Lord of Scribes, Keeper of Memory. A more authoritative reciter would be hard to find. Who better to guide us through the savage and exotic story of the founding and early fortunes of the House of Ptolemy, which lasted from the death of Alexander the Great in 323 B.C. until shortly before the birth of Christ?

Thoth is revealed not only as bossy -- an attribute natural in a god -- but also irascible, boastful, pompous, plaintive, sad. By turns he can be dispassionate, querulous, gossipy, full of wonder at the human follies he unfolds. He finds the right tone and shows himself inexhaustibly knowledgeable, whether speaking of Greek cremation customs, the fighting tactics of the Macedonian phalanx, the equipment used in the siege of Rhodes or the sexual expertise of Thais of Athens, Ptolemy's concubine and the most famous whore in the world. We follow the rise of Ptolemy from humble soldier to pharaoh of Egypt, a god in his own lifetime, and trace the doomed lives of his offspring. This is a story of tremendous scope, full of incident and adventure, dealing with the broader issues of politics and power, as well as the fascinating minutiae of a society far distant from our own. Thoth knows the value of doubt, of suspended judgment. He can tell us what memories Ptolemy suppresses; he can tell us -- he might be the only one who can -- that on Alexander's disastrous march through the desert of Gedrosia, when 60,000 men perished, Ptolemy ate goat droppings and rotten lizards and spiders and thistles; but Thoth cannot be sure whether it was two talking crows or two talking snakes that saved him on the desperate journey to the oasis in the Libyan desert to consult the Oracle of Zeus Ammon. And was it really true that Alexander's body showed no sign of putrefaction after 10 days in the midsummer heat of Babylon, when you could fry an ostrich egg on a stone?

Wisely, Thoth does not commit himself on such matters. Or maybe, since he is incredibly ancient by this time, his memory is a bit on the faulty side. But he has intimate access to the thoughts of the reader, whom he addresses as Pupil-of-Thoth. He can wax angry at the pupil's obtuseness; he can sense the onset of boredom and promise excitements to come. By these means Duncan Sprott, who is a very intelligent and accomplished scribe, makes perceptive and amusing points about some of the problems all scribes encounter.

However, Thoth is sometimes right to suspect that he is boring us. He is too long-winded at times. However fascinating the details of dress and manners and ceremonial life in ancient Egypt, and however much one may admire the research that has gone into this vast historical reconstruction and the sustained feat of imagination it represents, sometimes one wilts under the sheer accumulation, sometimes one feels the impulse to dig a sacrilegious elbow into Thoth's ribs and tell him to get a move on.

And because he is a god he hovers above the stream of life without so much as getting his toes wet. This gives him a good overall view, but he can't tell us much about the inner lives of those in the water. He does not give us the words they exchange; he does not tell us what they see when they look at each other, what they learn about themselves or life in general. Thoth is not curious about moral choices; he is not subtle in matters of psychology. To compensate, he is very interested in madness and crime. To take just one example among many, he relates the anguished love of Arsinoe Beta, Queen of Thrace, for her son-in-law, the beautiful Agathokles, and the wickedness it led her to, in an extended passage that is compelling to read and totally convincing.

In the last line of the book, Thoth threatens to fight any man who speaks ill of his account. So as a reviewer I am in the front line. But of course he knows that no story is ever without some lack in the telling. Duncan Sprott has vividly evoked for us a fascinating era and done it with a vitality and resourcefulness rare these days. So let there be peace. *

Barry Unsworth's most recent novel is "The Songs of the Kings."