Joseph R. Cammarosano 
The Contributions of John Maynard Keynes to Foreign Trade Theory and Policy, 1909-1946 [PDF ebook] 

Over the course of his life, Keynes often abandoned ideas previously developed and at times assumed positions which were contradictory to his earlier thought. This inconsistency, it is charged, is especially true of his thinking in the field of international economics where he alternated between fee trade and protection. This book, first published in 1987, examines in detail the positions that Keynes adopted in the years 1909-1946.