The author J. R. Hartley and his book on fly fishing do not exist in external reality. They are instead a product of the advertising fantasy world, dreamt up to promote the Yellow Pages. This advertisement was at its prime when I was trying to develop a suitable analogy for teaching medical students and junior doctors about psychotherapy and some of its techniques. When taking a short break in front of the television set, it suddenly struck me just how appropriate this advertisement was. J. R. Hartley himself lends credence to the analogy, while fly fishing as a sport provides an excellent comparison for the art of psychotherapy. Like the fictitious publication in the advert, psychotherapy and its techniques can prove exasperatingly elusive, as they constitute a series of shared internal beliefs and representations which exist largely within the collective mind. I therefore felt that this ambiguous character who is not part of the external real world, yet has a special inner meaning for a wide number of people, seemed like the ideal analogy for describing psychotherapeutic processes.