'This is a remarkable book, presenting an introduction to mathematical logic and axiomatic set theory from a unified standpoint … also eminently suitable for self-study by mature mathematicians who wish to acquire a well-balanced and deeper knowledge of a field that is not part of their specialty … The author's presentation is a model of clarity, and much of the liveliness of a lecture has been preserved in the write-up. The various asides, cross-references, and care in motivating definitions and concepts all contribute to the value of the book as an instructional source … a treasure in its genre, to be highly recommended by the reviewer.' MathSciNet

'… a real sense of freshness and vitality … I found this a very readable and stimulating book. Forster writes with an agreeably light touch and a whimsical sense of fun and his use of rectypes as a leitmotiv is both innovative and inspired.' The Mathematical Gazette

'The author's philosophical training leads him to accompany many definitions with lengthy reflexions which add interest and enliven the book.' Mathematika