Johnson devotes a chapter in his work Predecessors of Adam Smith: The Growth of British Economic Thought  (1937, reprint 1960) to Malachy Postlethwayt, Postlethwayt, the Publicist, p. 185-205.
Johnson's book "Predecessors of Adam Smith: The Growth of British Economic Thought" (1937, reprint 1960) focuses on Malachy Postlethwayt, the Publicist, and his contributions to economic thought.