In the General Introduction at the beginning of the first volume of Melanie Klein Today I gave a brief description of several main themes of theory and practice in Melanie Klein’s work and described how her theoretical innovations developed out of her attempts to conceptualize the newly discovered clinical facts that her work with children revealed. In the 1940s, 50s, and 60s the focus of research shifted to the study of psychotic and borderline patients, and this work again uncovered new clinical facts and led to new conceptualizations; it is these ideas that have formed the major themes of Volume 1. These areas of conceptualization have continued, but have in recent years been joined by a further theme, that of technique, which forms a major part of the present volume.