NONFICTION : THE SEARCH FOR OMM SETY by Jonathan Cott (Doubleday: $17.95; 236 pp., illustrated).

Somewhere around 1300 BC, in the holy city of Abydos, Egypt, Bentreshyt meets Pharaoh Sety I. Bentreshyt, 14, daughter of a vegetable seller and a common soldier, is an apprentice virgin priestess. In the delicious phraseology of the time, she and Sety “eat the uncooked goose.” Bentreshyt becomes pregnant; commits suicide rather than implicate the king. Sety, heartbroken, vows never to forget her. In the phraseology of another time, he ain’t just whistlin’ Dixie.

In 1907, Dorothy Eady, 3, falls down the stairs of her parents’ London flat. Pronounced dead, she revives and wants to go “home.” Home is Abydos, of which the child knows the minutest details, circa 1300 BC. She is the putative reincarnation of Bentreshyt.

Sety--or at least his “akh,” or astral body--visits her at night with increasing frequency. Until her death at 77--and presumably thereafter--they eat goose. Eady, meanwhile, has moved to Egypt, where she becomes a renowned Egyptologist, easily able to read hieroglyphs, to divine original layouts of ancient temples, etc. Living on little more than mint tea, holy water, dog vitamins and prayer, in a succession of hovels shared by cats, donkeys and pet vipers, she is nevertheless lucid, productive, feisty, witty, splendidly eccentric.

Cott’s book is none of the above, a rather plodding affair. Everyone from Carl Jung to Carl Sagan is called upon to explain--or disprove--the Sety phenomenon. Eady/Omm Sety would have chortled. Probably still does.