Product design is an active area of research. However, the term product design is non-uniformly discussed in the literature, especially in the field of industrial crystallization. There is often a distinction between product design and process design. Due to that fact there is an unclear situation which leaves room for discussions. This review should help to find a more clear position. The problem is that the interrelation of product and process design quite often is underestimated in the literature. Therefore, the interrelations are highlighted here based on four examples. The examples selected are randomly taken from the entire field of crystallization (commodities, solvates, polymorphs, batch crystallization). The principles and conclusions discussed can, however, be transferred to other non-touched areas where product and process design are considered. It is stated that no product design is possible without process design (control)".