Mitchell proposes a systematic approach to the formalization of architectural notions and reasoning and to the automation of architectural design. He introduces a “critical language” to express qualities of architectural objects. The language is based on the language of first-order logic with specific interpretations. Different qualities of buildings, including functional and aesthetic qualities, are expressible by formulae of the language.

The critical language is interpreted in a “design world,” which is, roughly speaking, a variety of architectural objects. For example, a world of “Greek-style villas” may be considered, and then the desired qualities of a specific villa may be expressed in the critical language. A design world is specified by specifying the basic graphical primitives and the grammatical rules of possible combinations and transformations of objects.

The specification of a concrete design world, as well as the expression of the desired properties of a particular building under design, is up to the designer. The design process itself is thought of as a derivation (or computation) in the design world, aiming to satisfy the properties stated in the critical language.

The presentation in the book includes numerous examples and illustrations, and the book ends with a 26-page bibliography. The book will appeal to people interested in architecture in general, and particularly in CAD systems in architecture.