SOME NOVELISTS MAKE you feel like you're looking into a mirror. The shock of coming upon one of your innermost thoughts, perfectly expressed, is both thrilling and unsettling--it's like someone is reading your mind. For the past ten years, devoted followers have been finding their thoughts reflected back at them in the characters of British novelist Margaret Drabble. The heroines have been distinctly individual women in varying situations, yet they have never failed to spark at least a flicker of recognition.

But even for seasoned Drabble lovers, her seventh and latest novel, The Realms of Gold, is extraordinary--as extraordinary as its heroine, Frances Wingate. Frances is a famous archaeologist in her mid-thirties, triumphant in everything she turns to, whether it be discovering ancient cities, delivering lectures, raising kids or giving dinner parties. When the book opens, she has recently broken off an affair with her lover of seven years, Karel Schmidt, although she still carries his false teeth with her on lecture tours, along with photographs of her four children.

She would almost be too much, if it weren't for Drabble's skill in creating characters that are so genuine that their eccentricities become not only acceptable but absorbing. Their reality has little to do with external characteristics such as Frances' impressive credentials; for the most part, action accedes to thought. Frances suffers from anxiety at the "seeming inevitability" of her success: "I must be mad, she thought to herself. I imagine a city, and it exists. If I hadn't imagined it, it wouldn't have existed. All her life, things have been like that."

What distinguishes The Realms of Gold from Drabble's earlier works is that she exposes the minds of characters other than her heroine. But she does so as part of her exploration of Frances Wingate, for Frances "would like to know where she began and the family ended." She returns to the town in the flat English Midlands where her father grew up and where she spent school vacations, trying to unearth her past in the same way that she had discovered the ancient city of Tizouk in the middle of the Sahara. What she finds is pretty grim:

We seek golden worlds from which we are banished, they recede infinitely, for there never was a golden world, there was never anything but toil and subsistence, cruelty and dullness.

Ah, if I believed that, she said to herself. But we unearth horrors, and justify them.

FRANCES MUST JUSTIFY them in order to survive and "prove the possibilities of the future." Her nephew Stephen, confronted by the same problem, can't see his way to such a justification and denies the possibility of the future by killing himself. The other characters in the book--two cousins Frances meets in the course of the novel, her brother Hugh, her father--seek their solutions in forms of solitude, even after the death from starvation of a neglected great-aunt reveals the hazards of such a course.

Their solitary thoughts form separate sections that are strung together like so many pieces of reality, doing away with chapters or divisions based primarily on action. Drabble succeeds with this difficult method, and she needn't intrude, as she occasionally does, to inform the reader of what she is doing or to comment on a character. Frances and the other characters stand on their own: they don't need any explanation.

Something else does, though, and that is the affair between Frances and Karel. They take it for granted, and the reader is forced to as well, because there seems to be little reason for and even less development in this love. But the unreal quality of their relationship in no way makes either of them less believable. Like the interfering omniscient narrator, this flaw is superfluous and can be ignored without damage to the novel as a whole. As she continues to widen her scope and refine her technique, Drabble will probably take care of these imperfections next time around. By then, the mirror should be polished.