KINDER THAN SOLITUDE. By Yiyun Li. Random House. 312 pages. $26.

Chinese American writer Yiyun Li introduces "Kinder Than Solitude," her second novel, with an epigraph from Romain Rolland: "You can't both live and have lived, my dear Christophe." Within the first few pages, Boyang, one of three characters we first meet as Beijing teenagers, offers a complementary riff on the same subject: "The best life is the life unlived."

The whole of the novel pivots on the question of what it means to live. Where is the best life? The past? The imagination? The life unlived lies in wait, sucking characters back into the past or pulling them into other dreamy substitutes for the real thing.

The novel starts in a crematorium, where a single designated mourner, Boyang, makes arrangements for the body of his old friend, Shaoai, who has been in a coma for 21 years. Her death, finally, is more a nuisance than anything - the long-deferred culmination of an old calamity. The exact nature of the event, one whose reach has stunted many lives, remains a mystery.

All that anyone knows for sure is that somehow Shaoai ingested poison. The fatal chemical had been taken from Boyang's mother's lab at the university. The uncertainty leaves open many possible scenarios and many possible culprits. Was Shaoai the victim of an attempted murder? Did she botch a suicide attempt? Was it a freak accident? Political motives can't be ruled out either; Shaoai was a radical who, in the wake of the massacre at Tiananmen Square, refused to recant.

Li has not written an overtly political novel, although everything that happens is shadowed by the tragedy at Tiananmen Square. She makes us aware of the panorama of history even as she trains her eye on the small and personal. Li travels in and out of the minds of her three teenagers: the brilliant Boyang, the optimistic Moran, and their new companion, a frosty but charismatic orphan, Ruyu.

This floating perspective is quietly attentive, dreamily paced. All three were implicated in Shaoai's poisoning. They dispersed that summer and never reunited. Each narrative returns in memory to 1989, when their paths split, and tracks their subsequent damaged lives.

The 1989 chapters, if pooled together, make a taut story of lost innocence. These chapters are also vibrant with communal life, a sad counterpoint to the untethered present lives of her trio of narrators. Boyang continues to help with Shaoai's care, as he imagines the others have been storing a hoard of experiences over the decades: marriage, career, children, wealth. He is a rich womanizer to whom nothing sticks. Ruyu is in California, living alone after failing at marriage. She works as a provisional caretaker for a group of women who need dog-walkers, house-sitters, weekend nannies and help with party planning. Ruyu finds little to care about and can't claim to be "someone definite."

Moran, describing her own isolation, observes that, although she misses "the poignancy of great happiness and acute pain," her life has its benefits, chiefly "the blessing of solitude." She arrives in the United States with two suitcases and a disposable husband. A drudge worker for a pharmaceutical company, she has continued to "travel lightly," hewing to the two-suitcase standard. Like Boyang and Ruyu, she is also a caretaker. Her present is the most love-filled. Although she divorced her second husband 11 years before, Moran visits him once a year for his birthday and imagines that in his obituary, she will register as the loving ex-wife left behind.

It is Moran who gives the novel its title. While the plot has more than its share of melodrama, Moran walks across the battlefield of the present delicately. She has been afraid, as have Boyang and Ruyu, to meet another person like herself. But she is also "afraid of never meeting another person like her, who, briefly, would look into her eyes so that she knew she was not alone in her loneliness." How to live in the aftermath of innocence, with the loneliness of unmet dreams: This is Li's magnificent topic. As her ex-husband is dying of cancer, Moran makes the choice to return to him. A person, she finally knows, is "kinder than solitude."

Reviewer Catherine Holmes teaches English at the College of Charleston.