This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book is about the therapist's professional matrix, both visible and invisible. It is also about how we, as clinicians, manage the web of professional connections that inform, control, bother and console us whilst we struggle with our client's inner world. These include connections with referrers, supervisors, co-therapists in conjoint work with couples, and particularly, colleagues with whom we find ourselves working concurrently. These professional networks of psychotherapists have been helpfully thought and written about elsewhere both from a psychoanalytic perspective, and from a point of view based in systems theory. The therapeutic function which S. Freud thought of as interpretation, and W. Bion as alpha function, serves to widen speculation, and ease the burden of the mystery of human experience.