The Cabinet of Light: Time Hunter, Book 1

Honoré Lechasseur, a "fixer" with time-sensitive abilities, is hired by Emily Blandish to find someone known only as Doctor Smith. He soon discovers that Doctor Smith is a legendary figure that has drifted in and out of Earth's history. As he follows the trail of Doctor Smith, questions arise: what is the Doctor's connection with 1949 London and with the mysterious "cabinet of light" that another group is seeking?