AbstractThe recognised complexity of the innovation process not only makes it difficult to manage, explain and study, but also presents problems for the development of a generalised model.Cooper's recent article in ‘R&D Management’ suggests that the construction of a generalised model is inappropriate because there appear to be a number of different types of innovation processes. However, many of the studies of innovation postulate or assume a general model which represents the stages involved in the firm.This paper reviews the models of the innovation process which have been proposed and the author classifies them according to his taxonomy of different types:(a) Departmental‐stage models(b) Activity‐stage models(c) Decision‐stage models(d) Conversion process models(e) Response modelsThe advantages and disadvantages of each approach are discussed and the conclusion reached is that still more research needs to be concentrated on the nature of the innovation process within the firm itself. The absence of a definitive model compounds the problems of semantics and definitions when discussing i