The intellectual history of the fourteenth century is still little known. Apart from the great figures like Ockham and Wyclif we have no detailed knowledge of the leading thinkers or the movements which may be deduced from their work. Dr Leff explains Bradwardnie's system of thought and relates it to the ideas of his contemporaries; these contemporaries are shown to have had their own differences of outlook, and the fourteenth century as a whole is also shown to have differed greatly from the thirteenth.