A fast-moving, murder mystery with a remarkably consistent recreation of late nineteenth-century medical Paris. Psychiatric theories of degeneracy, heredity and race inform the responses of the medical characters. Zealous researchers strive to establish connections between brain pathology and behavior, occasionally resorting to crime to advance the cause. The plight of women denied independence and employment is another major theme developed in several characters; they find release in cross-dressing, prostitution, manipulation, hysteria, perinatal death, and suicide.

While the prose is occasionally overblown and the emotions starkly drawn, the plot moves along smartly. The apparent guilt or innocence of an array of suspects flips back and forth with compelling effect. Notwithstanding protestations of tolerance, anti-semitic sentiments pervade medicine and society in both Paris and Boston. Even James must confront his suppressed suspicions and guilt over the end of his own tepid marriage with his wife's miscarriage and death.