AMBIEN II is a member of the Five, a group of administrators who run the Sirian Empire, an interstellar civilization. The novel is her account of her activities on the planet Rohanda (Earth), and the story of her growing skepticism about her society's purpose.

Ambien has come to Rohanda to conduct an experiment with the Lombais, a group of people theSirians have removed from their own planet. The Sirians, however, must share Rohanda with Canopus, an old enemy with whom Sirius is now at peace; the Canopeans are conducting their own experiments. People of Shammat, a third civilization, also make an appearance. The Canopeans are a highly evolved people Ambien distrusts; the Shmmatans are cruel, greedy and barbaric. Through her encounters with two Canopeans, Klorathy and Nasar, who become her mentors, Ambien comes to oppose her own society.

The scope of the novel is vast. All of Earth's history is merely the background of Ambien's story, since she lives for millions of years. Our ancestors, it seems, were the products of biological experiments; we have the ethical and mystical leanings of Canopus, the empiricism and technical expertise of Sirius, and the evil, grasping nature of Shammat. Catastrophes and great changes are passing incidents to these long-lived people, part of a pattern that the Capopean Klorathy calls "the Necessity."

In her introduction to this, the third in a series of visionary novels using the devices of science fiction, Doris Lessing gives us a yardstick with which to measure her accomplishment; her cosmolgy is "only for literary purposes," but our ideas about out history are probably wrong; we may have forgotten ancient sciences; visits by UFOs have very likely taken place; we may be surrounded by artifacts which "might have . . . functions we do not suspect." She mentions her own preoccupations with "the group mind, the collective minds we are all part of, though we are seldom prepared to acknowledge this . . . with billions and billions . . . of us on this planet, we are still prepared to believe that each of us is unique."

Lessing has set herself a difficult and contradictory task: to explore the notion that each of us is part of a cosmic pattern, she writes a novel, a form which emphasizes the individual's importance. She wishes to deal with large issues: the colonial mentality (Ambien is appalled at brutality, yet thinks nothing of removing "primitive" beings from their home world and experimenting on them); the place of technology (the Sirians, under the spell of "progress," are without purpose and suffer from depression); historical processes (Ambien discusses these in the language of a social scientist, certainly a barrier to enlightenment); and the battle between good and evil (Ambien comes to see thata evil must exist for good to be possible).

"I would so like it," Lessing writes, "if reviewers and readers could see this series . . . as a framework that enables me to tell . . . a beguiling tale or two; to put questions, both to myself and to others; to explore ideas and sociological possibilities." This would be a worthy goal for any novelist, but The Sirian Experiments falls short of it. Lessing's cosmic, often haunting vision is marred by details from pop pseudo-science and pulp fiction. The villianous Shammatans glower and swagger; Nasar and Klorathy sometimes sound like trainers at an est seminar; Atlantis makes an appearance and disappearance; planets are subject to cosmic "forces" and "vibrations" never fully explained; "bursts of radiation" speed evolution; the Navahos and Hopis are descendents of two tecnicians named Navah and Hoppe. The novel's serious intent is lost in these trappings. If ideas "flow through humanity like tides" as Lessing asserts, then the tide of Velikovsky and Von Daniken, of ancient astronauts and unlikley catastrophes, has washed up on her shore.

The internal logic of the book also seems faulty: would the advanced Sirians really need to rely on a kind of slave labor? This, combined with an apparent lack of knowledge about the sciences, astronomy and biology in particular, robs the novel of conviction; present-day science would have provided more authoritative symbols. c

It's a shame. Lessing, unlike many "serious" novelists, knows one can write a serious book using a science-fiction framwork. She is among the best realistic writers, but this book obscures her gift. Ambien II is characterized almost too well, which is ironically a problem. Ambien thinks like a bureaucrat, so the reader often gets lost in tedious descriptions and itineraries, while the narrator passes over potentially interesting events with little comment; one begins to wish Lessing had served as Ambien's editor

There is also an anti-rational tone to the book; reason itself becomes a barrier to understanding, and Klorathy and Nasar leave a lot unsaid; which Ambien must then grasp through a leap of faith. Reason alone cannot widen our vision, but a vague, inexpressible mysticism is not necessarily a panacea. With growing irrationality on all sides, do we really need another attack on reason?

The book is not completely unrewarding; Lessing is too good of a writer for that. Ambien's encounter with the "fallen" Nasar is moving and frightening, and I would like to have seen more of the Shammatan, Tafta, who could have become a complex Villian. Occasionally one glimpses the Spinozistic vision permeating the book. But a great craftsman cannot do his best work with inferior materials and poor tools, and a writer cannot write a good book which is meant to be more than entertainment with secondhand ideas and cast-off junk. Both Doris Lessing and science fiction deserve more.