Why should modern psychotherapists be interested in philosophy, especially ancient philosophy? Why should philosophers be interested in psychotherapy? There is a sense of mutual attraction between what are today two thoroughly distinct disciplines. However, arguably it was not always the case that they were distinct. The author takes the view that by reconsidering the generally received wisdom concerning the history of these closely-related subjects, we can learn a great deal about both philosophy and psychotherapy, under which heading he includes potentially solitary pursuits such as "self-help" and "personal development".