ABSTRACT
Chapter 1 serves as an overture. It introduces the GTPI, framing it within the cultural semiotic psychology theory, and discusses some epistemological and theoretical premises on which it is based – the vision of scientific knowledge, the relationship between scientific knowledge and intervention, and how to understand the unity the GTPI aspires to. The chapter also offers an overview of the four components of GTPI – theory of the object, theory of change, theory of action, and theory of the client. Each of these theories is the subject of one of the following chapters.
