Second Thoughts is a collection of papers on Schizophrenia, Linking and Thinking, and is a commentary upon them in the light of later work. Originally composed between 1950 and 1962, it derives its title from the lengthy critical commentary which Bion attached to these case histories in the year of publication, 1967, and represents the evolutionary change of position marked in his three previous books and brought to further refinement in the present work.