Set in 1966 at a summer house in Rhode Island, "Double Lives" portrays an upper-class, conservative Washington family faced with the changing mood of the country and conflict within itself. Christopher Nicholas, the father, has just retired early from the CIA, amid the repercussions of the Bay of Pigs fiasco. His failure, and the reticence and decorum that have guided his life, make it difficult for him to seek comfort from others in his family. Joanne, his beautiful wife, nonetheless radiates grace and elegance, holding them all together with her tact, humor and good will. Katherine, the eldest daughter, is sympathetic but preoccupied by questions of sex and marriage; Bucky, the son, unformed and looking for his father's love; Diana, 17, is volatile, moody, and self-hating with the passion of adolescence.

The story focuses on Diana's emotional search for self-understanding and definition, paralleled by Christopher's efforts to comprehend his past and character in light of present failure, and the tension between the two. The father-daughter relationship serves as a metaphor to explore authority vs. rebelliousness, maleness and femaleness, and the perspectives of age and youth. Christopher and Diana are both strong personalities, but where she expresses herself through deviance, Christopher depends on control. "He was disturbed by thoughts of people dying when they weren't prepared to die -- of people dying while their lives were unsolved or in terrible messes." He dreams of having to deal with Diana while her woman's blood gushes from under a closed door and he tries to stem its flow: "He didn't want to hide anything or to avoid disturbing knowledge; he just wanted to get the mess so it was manageable, so men of good will and common sense could discuss it." He struggles to understand why a disciplined, dedicated life has left him empty.

Christopher's limits are those of his class and generation, the limits of an outlook based on power to interpret the complexities of human nature, morality and even politics. His doubt hits so deeply because it is more than personal; it reflects the questioning of attitudes and values by an American confused over Vietnam, the CIA and the rightness of its role in the world. Barnes assumes the reader's knowledge of that time and sketches it only briefly in discussions with Christopher's liberal neighbors, the Bakers, but it forms the essential backdrop to his musings.

If Christopher embodies traditional male attitudes even in his self-examination, Diana perceives herself as more complicated. She is confused by gender, the "masculine" and "feminine" pulls of her nature, but she, too, has a traditional view of which qualities fall into each category. She equates authority with maleness and feels oppressed by it -- "power was behind the power on the throne . . . power ruled by force, through class and sex." She both wants to be a boy, and to love one. She feels an undefined attraction to Mrs. Baker that is never fully explained or explored, but seems to lie not in similarity of sex but of character. To escape her murky self, she takes on the identity of others around her. She repeats her sister's words and tries to feel her idealism, mimics the voice, walk and tough detachment of her sister's boyfriend.

Much of the book follows Diana's changes in mood, shifting style and tone as she jumps from anger to despair, self-pity, embarrassment, hope or amusement. The effect is uneven, something like living with someone unstable, with passages both deft and excessive. Barnes is sensitive to nuances in character and details that illuminate it, and her prose can be evocative. She writes, for example, of Christopher admiring the color of a wall, "this pale, pale purple suggested the limits of human perception, the last thing anyone could say before becoming spirit itself. The color pleased him in the same way as Greek pottery or . . . Aztec technology. He was moved . . . by evidence of intelligence and order . . . from the past." Yet her language can also be awkward, abrupt, or obvious, perhaps reflecting Diana's nature, but intruding as well.

So much goes on in Diana's head alone that it limits the possibilities with other characters. There are few direct scenes between Diana and Christopher, or Mrs. Baker, although her feelings for these adults are central concerns. Barnes is onto something when she has Diana try out the personalities of people she loves. We test ourselves, we see ourselves, in relation to others. More happens when people connect. Diana's dialogue with Katherine is the most natural, the most engaging, because it is ongoing. When she breaks out of her cocoon of silence to talk to Christopher, the result is often stilted and unsurprising: "Men were like this absolute police force because we had to do what you told us to," she tells her father. When, instead, Barnes steps back to give a portrait of the family, she unfolds a richer pattern and past that binds people together despite the implacability of their secret selves.