Diseases of Field Crops in Canada has enjoyed incredible success since the publication of the first edition in 1984, and then again with revisions in 1988 and 2003. The popularity of this book amongst technical specialists and students in plant pathology courses, as well as agronomists and growers, has required redevelopment of the most recent edition of this book to be updated in order to meet ongoing demand and the current scientific understanding. The fourth edition of Diseases of Field Crops in Canada has been extensively revised, a team effort that relied on the contributions of many.