This was the first Time Travel story I ever read and I have been hooked on Time Travel and Time-slip stories, a whole sub-genre of SF and Fantasy, ever since.
Now, reading it again, I can see why. It really is very good.
Tallahassee Mitford, a modern American with a PhD in Egyptology, is suddenly time-shifted from the museum where she works back to ancient Egypt. She wakes up on the hot sand with the ankh she had been studying still clutched in her hand and a dead woman, the image of herself, lying beside her.
That would be traumatic enough, though she could handle it – Tallahassee is nothing if not resourceful – but this is not our ancient Egypt. It is another, rather different, civilisation in an alternative universe. In this world, "though Egypt had fallen to invaders, first Greek and then Roman, even as in her own world history, it had not been lost. Retreating south to Kush, the modern Sudan, those of the Heirarchy who had survived again brought their civilisation to a peak." They called this land Meroë, but after a few hundred years it too fell, and "the refugees – the royal family and what was left of those with the Knowledge – had fled westward." Again their civilisation flourished. "There followed a peak of prosperity and success that lasted for nearly two centuries. But what favored their safety was the fact that in this world there had arisen no Mohammed, no way of Islam to drown in blood the central African states, as had happened in the history Tallahassee knew."
But now an invader from another time or space – or another space-time continuum – had arrived. Just one man, known as Khasti, but with the aid of his vastly superior technology he was taking over the country. Who was he? Where was he from? Was he really alone? If so, why?
Tallahassee finds herself cast as Ashake, who is one of the very few left with the Knowledge, the Power. As Ashake she is also heir to the throne of the Candace. And before the question of how – and whether – to return to her own world arises. she must play a pivital role in the battle between magic and technology, between good and evil.
Is magic always good, technology always evil? Ah, what a question.