Hundreds, if not thousands, of psychotherapy methods have been described. If you have a very liberal mind, you can rejoice in such an “offer”: A chacun son bonheur!1 (as they say in the bazars of France). Indeed, such a profusion, undoubtedly a reflection of the complexity and creativity of the human mind, could be welcomed if we had tools to guide clients in choosing a therapy. However, to our knowledge, there is no unified framework where the different types of therapy can be described, their specificities mapped and their indications outlined. In fact, each school of therapy is rather accustomed to developing on its own account, each claiming to be well founded in clinical experience. The universe of psychotherapies seems to the naive psychology student somewhat compartmentalized between the worlds of these different schools. In particular, a deep canyon seems to separate the bases of cognitive-behavioural therapies from those of psychodynamic or existential therapies. Some build on experimental psychology, others on intuitions about subjective life and the experience of the relationship.