In prose as clean and precise as a neurosurgeon's work yet also lyrical and at times beautiful, Flitter recreates the life-or-death drama of brain surgery as he has practiced it for more than 20 years. Although he strives for emotional detachment, his gripping stories are heartbreaking and deeply moving, peopled with the specters of patients he has lost as well as of those who recovered. Among the memorable patients described are Anne, his first love and prospective wife, whom he treated for a tumor but could not save from death; Hampton, a drug dealer shot twice in the head; Chris, an eight-year-old boy injured in a skateboard accident; and Judith Halpern, victim of a malignant brain tumor, whose death haunts the Pennsylvania neurosurgeon. Although he devotes too much space to the suicides of medical-school classmates and colleagues, to the deaths of close friends, his father and grandfather, those souls function here somewhat like a Greek chorus, reinforcing Flitter's conviction that death is part of a voyage of understanding and accepting who we are. His remarkable book makes the operating room a theater of human drama, tragedy and occasional triumph. (Apr.) FYI: The ""pavilion"" of the title is what Flitter named a wing of an imaginary hospital.