In recent years optical communications and optical signal processing have experienced remarkable progress. This is essentially due to the advent of fibre optics. This paper deals with theoretical and practical aspects regarding fibre optics, with particular attention to some recent applications, and to the most attractive future perspectives. In order to give an exhaustive treatment of this subject, some related technologies are discussed as well, e.g. optical sources and detectors, semiconductor opto-electronic and photonic devices, and crystalline and polymeric materials for non-linear wave interactions