With her first novel, "Bonjour Tristesse," Françoise Sagan established herself as a phenomenon. With her second, "A Certain Smile," she indicated her staying power. With her third, it becomes possible to define, in some degree, her talent. For there is talent here, limited perhaps but more than superficial….

Within a certain range she has a sort of psychological "absolute pitch." The small immediate reactions of her characters are true and telling enough to breathe life even into the ones who have been sitting around Paris ever since they got lost there thirty years ago, when the sun also rose. Besides, her own curiosity and appetite for living belie every bit of the dismal "philosophy" with which her men and women attempt to console each other.

What Miss Sagan can't do—not yet, at any rate—is to plot. Her enormously ambitious plan [for "Those Without Shadows"] is...