The task of this paper is to give an overview of the most influential models of planning that have been developed during the second half of the 20th century. We will present each model of planning just as it is discussed in the technical literature of planning theory. In doing so, we will only trace the main lines along which the planning - theoretical discussion has developed, even though there obviously are many different approaches to planning over and above what we will discuss here, i.e. any list of planning forms and styles could be extended almost indefinitely. Any approach that lies beyond these main lines of development will not be considered beyond this point. .