Of the work in embodied philosophy and cognitive linguistics, this by far the most careful, cogent, and through exposition. It is not light reading--it assumes a high level of education and a high degree of familiarity with Western philosophy, but it is profoundly rewarding.
Johnson develops a theory of image schemas as the preconceptual links between our embodied experiences and our sophisticated abilities to use language, including the theory of conceptual metaphor he codeveloped with George Lakoff. He offers many different sources of evidence ranging from gesture to studies of epistemic modality in logic and linguistics to phenomenology to aesthetics and art. The second half of the book largely explores the philosophical, historical, and psychological elaborations of the notion of a schema.
All in all, those searching for an exposition of how the repeated patterns of bodily experience shape cognition will be rewarded. The twenty-odd diagrams of image schematic patters are also highly revealing.
Similarly, academically-minded skeptics who are unconvinced of the rigor and merit of the research programme he outlines with Lakoff in Philosophy in the Flesh should find this satisfying and challenging reading.
The book is not without faults, but largely in the unacknowledged contributions of other strains of thought. For example, Johnson does not explore the relationship between image schemas and Wertheimer's theory of gestalt perception; nor does he acknowledge here any relationship to Merleau-Ponty or the Piagetian tradition of child development; and the Shepard-Metzler mental imagery studies of object rotation are only briefly mentioned. Such ommissions may be more a result stemming from a limited scope, however, as he has acknowledged such thinkers elsewhere.