Anne Perry's William Monk series starts with "The Face of a Stranger" and continues with "A Dangerous Mourning" and "Defend and Betray." Some of her more recent titles include "Execution Dock," "A Sunless Sea" and "Blind Justice." "Corridors of the Night" is her most recent book, as of September 2015.
In "The Face of a Stranger," set in 1856 London, police detective William Monk must investigate the murder of a Crimean war hero. Monk has lost his memory in an accident and fears he may have committed the crime himself. He meets the nurse, Heather Latterly, who assists him and becomes his wife over the course of the series.
In "Corridors of the Night," the doctor of one of Hester's hospital patients is Magnus Rand. Hester learns that he and his chemist brother are buying children to use in experiments. To keep her from exposing them before they finish finding what they hope is a miracle cure, they take her prisoner along with the children. Monk must find them before their time runs out.