The use of growth functions for estimating developments in consumer demand is already rather old. In many books on 'mathematics for ecomists' one can find one or more examples of growth functions, however, usually without any ecomic considerations as a background. Furthermore there are many ecometric contributions on the subject scattered over many books and journals. In this book - the English translation of the author's doctoral thesis - , Dr. W.J. Oomens gives a highly unified treatment of the subject. The book consists of two main parts, preceded by an introduction and concluded by an application. The first main part starts with a discussion of the general tions underlying the theory of the development of demand for new consumer durable goods and next describes the many models kwn from the literature, using these general tions. Because of the unified treatment the author succeeds in clearly ranking the different models, in presenting the aspects they have in cornmon and in explaining the properties which are different in the models being described. The critical discussion of the existing models leads a.o. to a new model, the 'heterogeneous generalized logistic model', in which environmental variables are inserted into the purchase propensity function as well as into the function for the variable saturation degree.