In volume 1, which is divided into books 1 and 2, Alexander begins with a review of mind, analysing the experience of experience itself, and concludes that minds and external things are co-ordinate members of a world. The analysis leads to the suggestion that space and time may, in a strange way, be the foundation of all being. In book 1, ‘Space-Time’, and book 2, ‘The Categories’, Alexander examines in detail the relation between space and time and thereafter focuses on the categories.

After discussing physical space-time and its perspectives and sections and mental and mathematical space and time and the relations between them, he concludes that physics, psychology and mathematics are dealing with one and the same space and time. The differentiation among the sciences is only a point of different degrees of directness within procedure. Furthermore, space and time are the same reality considered under different attributes.

In book 2, Alexander presents the nature of the categories of existence, universality, relation, order, substance, causality, reciprocity, quantity and intensity, whole and parts, numbers and motion. He examines also their relation to each another, dividing them into three groups. The major categories, forming group one, are existence, universality, relation and order. The second group of categories (substance, causality, reciprocity, quantity and intensity, whole and parts and numbers) communicate with each other and with the four major categories of group one, though the categories of group one do not communicate with those of group two. The concept of motion underpins the third group of categories. It presupposes the other two groups and communicates with them, whereas they do not communicate with it. Book 2 closes with chapter 10, ‘The One and the Many’, in which Alexander leads into final thoughts about space-time, expounding, amongst other things, the relation between space-time and the categories.

In volume 2, containing book 3, ‘The Order and Problems of Empirical Existence’, and book 4, ‘Deity’, Alexander conducts a philosophical investigation of various types of existents, expounds their relations to one another within space and time, and finally discusses the nature of deity.

In book 3, he considers, among other questions, whether the relation of mind to body and the relation of mind to its objects are unique. Alexander attempts to expound the manner in which the different orders of empirical existence are related to each other. Starting with chapter 1, ‘The Clue to Quality’, he analyses mind, its neutral basis and the apprehension of other minds; he continues the discussion in chapter 2 ‘The Order of Empirical Qualities’. In chapter 3, ‘The Empirical Problems’, he shows how the problems he has been discussing arise and should be presented. Then follow chapters on mind and knowing, mind and its acts, the ways of apprehending categories and qualities, appearances, illusion and ideas, value and freedom.

In book 4, in the course of three chapters, Alexander reflects on deity and god, on deity and the religious sentiment and finally on deity and value.