"We have proof now that a spectacularly great island-city really did exist in the middle of the Atlantic Ocean thousands of years before Plato's time, and that it really was destroyed by a gigantic cataclysm . . . ."

Roy is an observer who goes back to 18,861 B.C. when he invades the mind of Prince Ram, heir to the throne of Atlantis, a city which is "Iron Age living in Stone Age times.""Letters from Atlantis" is a series of Roy's letters (with Prince Ram as scribe while in a trance) to his friend, Lora, who is harbored in the mind of an official of the same prehistoric era in an eastern land that will someday be Poland or Russia.

The idea of mind-travel, invading the mind of inhabitants of a time period without their knowing it, is the theme around which this novel is set. This time warp allows the observer to be "implanted in another man's body while my own lies sleeping in a laboratory at the other end of time . . . since it's physically impossible for us to travel through time except as intangible electrical impulses . . . it does allow us to recapture all kinds of astounding knowledge that otherwise would have been lost forever."

But Roy feels the guilt of invading another person's life. "There's even a name for it, isn't there? Observer Guilt Syndrome . . . being a time-traveler involves being a sneak and a snooper and an eavesdropper on somebody else's most private moments."

Atlantis is indeed a glorious empire and Silverberg describes the advancements of the technology in detail; boats that are propelled with engines and electrical-type lights. The hierarchy of the ruling class, the relationship with the "people of the land" and the intricate religious ceremonies are outlined in an impressive imagery. The author continues to remind the reader - through the voice of Roy - that "people of future ages will come to think of its very existence as nothing more than a pretty myth."

It is refreshing to have such a well-rounded character as Roy in a science fiction novel. His sensitivity and dedication is evident even though he is actually just a figment of a person's mind, trying to seek meaning, record history and advance the understanding of a lost society.

It is when Roy tries to control the prince's mind, as he had his body for the purposes of being his scribe, that the feeling of a ticking bomb is felt. "I was tempted to reach in and try to defuse him . . . then at last he spoke . . . like a bomb going off right in my face: `Who are you demon, and why are you within me?' "

Roy, against all instruction, admits his intrusion in the prince's mind and a level of reciprocity and acceptance takes place between them.

"Letters from Atlantis" is packed with motifs and metaphors for life and understanding of the Jungian psychology of collective unconscious, "Somewhere in our own world today are the descendants of these Athilantans."

Plato would have been delighted with the enrichment of the Atlantis story, I think, and its acceptance of fate and the "lessons the gods wish to teach."

"Letters from Atlantis" is one of a new series of novels, called Dragonflight, that are written for young readers by leading writers, each dealing with a major theme of fantasy.