The structure of this chapter is as follows: in the introduction, the main notions and concepts of innovation diffusion theory accompanied by names of their creators will be presented in historical order. Further, in the main body of the chapter, these notions and concepts will be presented in detail. The chapter will conclude will some discussion of possible future developments. Innovation Diffusion theory has been characterized by many trends in scientific reasoning. The history of these trends, the main elements and topics of innovation diffusion research mainly from in the period between the 1900s until the 1980s are presented in a comprehensive form in the four editions of the remarkable book by Everett M. Rogers Diffusion of Innovations (Rogers, 1962, 1971, 1983, 1995). Rogers recognized and analyzed the following areas of innovation diffusion research: cultural anthropology, early sociology, rural sociology, education, public health and medical sociology, communication, marketing and initial stage of the analytical modeling of innovation diffusion processes. Additionally three large areas of innovation diffusion research were also mentioned: geography, general sociology and general economics.