In our current professional climate, with calls for 'evidenced-based treatment', and in light of the prestige accorded to this emblem, we can ask: for what purpose do we seek evidence? For our students? For the public at large? For an inner sense of feeling supported by science? Most disciplines are concerned with cumulative knowledge, aimed toward self-affirmation and self-definition, that is, establishing a sense of legitimacy. The three parts of this volume are directed toward the goal ...