The aim of this book is to explore the theoretical possibility and the social function of a unified approach to every phenomenon of signification and/or communication. Such an approach should take the form of a general semiotic theory, able to explain every case of sign-function in terms of underlying systems of elements mutually correlated by one or more codes. A design for a general semiotics should consider: (a) a theory of codes and (b) a theory of sign production - the later taking into account a large range of phenomena such as the common use of languages, the evolution of codes, aesthetic communication, different types of interactional communicative behaviors, the use of signs in order to mention things or states of the world and so on. Since this book represents only a preliminary exploration of such a theoretical possibility, its first chapters are necessarily conditioned by the present state of the art, and cannot evade some questions that - in a further perspective - will definitely be left aside. In particular one must first take into account the all-purpose notion of 'sign' and the problem of a typology of signs (along with the apparently irreducible forms of semiotic enquiry they presuppose) in order to arrive at a more rigorous definition of sign-function and at a typology of modes of sign-production. Therefore a first chapter will be devoted to the analysis of the notion of 'sign' in order to distinguish signs from non-signs and to translate the notion of 'sign' into the more flexible one of sign-function (which can be explained within the framework of a theory of codes). This discussion will allow me to posit a distinction between 'signification' and 'communication': in principle, a semiotics of signification entails a theory of codes, while a semiotics of communication entails a theory of sign produciton. The distinction between a theory of codes and a theory of sign production does not correspond to the ones between 'langue' and 'parole', competence and performance, syntactics (ane semantics) and pragmatics. One of the claims of the present book is to overcome these distinctions and to outline a theory of codes which takes into account even the rules of discoursive competence, text formation, contextual and circumstantial (or situational) disambiguation, therefore proposing a semantics which solves within its own framework many problems of the so-called pragmatics.