Wilfred Bion was a potent and original contributor to psychoanalysis. He was one of the first to analyse patients in psychotic states using an unmodified analytic technique; he extended existing theories of projective processes and developed new conceptual tools. The degree of collaboration between Hanna Segal, Wilfred Bion and Herbert Rosenfeld in their work with psychotic patients during the late 1950s, and their discussions with Melanie Klein at the time, means that it is not always possible to distinguish their exact individual contributions to the developing theory of splitting, projective identification, unconscious phantasy and the use of countertransference. As Donald Meltzer (1979, 1981), Denis Carpy (1989, p. 287), and Michael Feldman (2009, pp. 33, 42) have pointed out, these three pioneering analysts not only sustained Klein’s clinical and theoretical approach, but through an extension of the concept of projective identification and countertransference they deepened and expanded it. In Bion’s clinical work and supervision the goal remains insightful understanding of psychic reality through a disciplined experiencing of the transference–countertransference, in a way that promotes the growth of the whole personality.