Highly regarded in England, Tremain has yet to win her discriminating audience here, although her seventh work of fiction, Restoration , brought her fine reviews on these shores. Her latest novel, shortlisted for the Booker Prize, is a deceptively simple but intensely imaginative work that explores the issues of sexual identity and the inchoate longings of those who have secret lives. In an epiphanic moment in 1952, when she is six, Mary Ward, the child of a poor farming family in Suffolk, realizes that she was meant to be a boy. Related with insight and compassion, Mary's struggle to change her sex is one component of a moving story that also illuminates her parents' disastrous marriage and the lives of other villagers. Brutalized by her father and emotionally abandoned by her mentally fragile mother, who frequently takes refuge in the local asylum, Mary is given succor by others. Tremain has a remarkable ability to create characters of shining, honest goodness--people capable of extraordinary decency, generosity and love. Mary's benevolent grandfather, a doughty teacher, an elderly widower who marries the mother of Mary's dearest friend--these people are sure of their places in life, and they try to help Mary deal with her transsexualism. If Mary (aka Martin) is not so appealing, if her misery makes her hard and self-centered, Tremain refuses to trivialize her hero(ine)'s ordeal. Other characters--Mary's brother, the village butcher's son who wants to sing country and western music in Nashville--also must find their own way, realizing as Mary does that ``we're all something else inside.'' Seen against the background of three decades of history and social change, this is an affecting and often quite humorous narrative that asks provocative questions and challenges the reader's perceptions about the essence of being. (Apr.) .