Experiences in Groups is a collection of Wilfred R. Bion's essays on groups, written during and after World War II. He wrote the first essay in collaboration with John Rickman, his former analyst. As in a Bionian sense the individual may also be seen as a group, basic assumptions can be seen at work within an individual. Rickman was the first to apply Klein's ideas to group psychology. Bion thought that working with groups differs fundamentally from a classic psychoanalytic approach. Wilfred Trotter was a professor of surgery at University College Hospital and the honorary surgeon of King George V as well as Freud. Bion uses the term binocular vision in different places in his work. Psychological and physical symptoms or emotional states can often be understood as coming from the protomental system. Nino Torres discusses the protomental matrix from a philosophical point of view. Bion's vision of the matrix in a group is often opposed to Foulkes' view.