The latest work by this versatile novelist (The Pilot's Wife; Fortune's Rocks) may be her most mature to date, as she demonstrates new subtleties in the unfolding of a complex plot. Proceeding in reverse chronological order, Shreve recounts the obsessive love between poets Linda Fallon and Thomas Janes; theirs is a highly charged affair, though they connect only three times in 35 years. The novel's three sections (""Fifty-Two,"" ""Twenty-Six"" and ""Seventeen"") refer to Linda's ages when she meets and later encounters Thomas first (last in the book's structure) as a troubled teen near Boston with ""only indistinct memories of her mother and no real ones of her father""; then in Kenya, where Linda has joined the Peace Corps and Thomas's wife, Regina, is working with UNICEF; and finally at a literary festival in Toronto where both characters, unbeknownst to each other, are guest speakers. Though each of the novel's segments is intensely powerful, the cumulative effect is especially wrenching, as the reader knows what Linda and Thomas have yet to experience. Their Africa encounter is especially gripping, since both characters are torn between their mutual passion and their love for their spouses. (Linda has also married, and Regina's announcement of her pregnancy adds further tension.) Shreve's compassionate view of human frailties a recurring theme in much of her work is at its most affecting here, as she meticulously interweaves past and present with total credibility. Her fluid narrative perfectly mirrors her protagonists' evolving temperaments and viewpoints, while her overall restraint serves to intensify the novel's devastating conclusion. (Apr.) FYI: The film version of Shreve's 1996 novel, The Weight of Water, starring Sean Penn and Elizabeth Hurley, is due in theaters later this year.