The author traces the historical development of secret diplomacy from the eighteenth century through great-power maneuvering and the wartime period, analyzing methods, motives, and key episodes. He argues that clandestine agreements and covert bargaining foster suspicion, erode public confidence, and undermine democratic accountability, contributing to the breakdown of trust during the great conflict and its settlement. The study examines parliamentary and public roles, compares national practices including recent American experience, and evaluates efforts to increase publicity and reform diplomatic practice while identifying political and institutional obstacles to eliminating secrecy.