This chapter argues that psychoanalytic couple therapy, like psychoanalysis itself, has made its fundamental discoveries about the unconscious dimensions of relationships. David Hewison distinguishes between three different genres of research. The first of these is psychoanalytic, based primarily on clinical case studies. The second he calls "psychological", mainly concerned with therapeutic outcomes. And the third is "social scientific" work which brings together interest in the internal dynamics of couple relationships with their wider social contexts. Hewison points out that the case load of tavistock centre for couple relationships has become enormously expanded through its merger with London Marriage Guidance in 2005. The most important field of research in this and other psychoanalytic fields lies not in the study of "treatment outcomes", but rather in giving a more accountable and systematic basis to the fundamental understandings of psychic process.