An overview of the aims and accomplishments of the two most prominent ""structuralist"" social scientists, Jean Piaget and Claude Levi-Strauss. Gardner readably describes Piaget's theory of stages of the growth of human reasoning power, and Levi-Strauss' attempt to find ""codes"" or patterned relationships in myths, cooking customs, kinship forms, etc., which will reveal the eternal workings of the human mind. Gardner goes on to discuss structuralist method in general, accurately locating it between raw empiricism and fideist speculation. He wants to make it out as super-scientific but has to acknowledge that, especially as practiced by Levi-Strauss, it may not even be a method which can communicate testable results. Part of the problem is Gardner's own vulgar idea of scientific observation, model-building, and experimentation. He is infatuated with the notion that the structuralists, through logical and mathematical apparatus he does not elaborate, bring social science closer to the ""hard"" sciences. Yet, although he himself seems to have done conceptually innovative work on children's thinking, he begs the basic philosophical questions. How does one select the ""underlying regularities"" and ""elementary forms"" basic to human beings? How does one know they ""reflect"" or ""determine"" -- Gardner uses these terms sloppily -- the structure of the mind? For a treatment of these sorts of problems a book like Edmund Leach's Claude Levi-Strauss (1970) is preferable. While Gardner substitutes a certain boosterism for serious criticism, he does provide a sense of the world-views of Piaget and Levi-Strauss, especially the latter's opposition to historical conceptions, his implicit denial of the importance of human creativity, and his preference for static, primitivistic ""structures."" To this extent the book is a stimulating, if incomplete, introduction.