However, as he began to read B.F. Skinner's work his viewpoint shifted towards radical behaviorism while still retaining a great respect for Piaget. His book, B.F. Skinner: A Reappraisal, is written as an evaluation of Skinner from the standpoint of a European psychologist, and he relates Skinner's work with that of such prominent European psychologists as Pavlov, Freud, Lorenz, Piaget, and Vygotsky. Richelle provides an overview of Skinner's career and how his views evolved over time. For those who are familiar with Skinner's work much of this should be familiar, but they still might learn a good deal from Richelle’s comparison of Skinner to his European contemporaries. Richelle's evaluation of Skinner in reference to European psychology makes his book unique among the studies of Skinner's work.