Modern linguists have their own rigourous and abstract techniques.
But in this intellectually demanding work C. S. Lewis, working at the height of his powers, takes the widest of perspectives, and retains depth of focus. The result is valuable exposition, with depth both in psychology and philosophy, and rich in literary source material. The words themselves are treated as living entities, evolving by expansion, contraction, and development of new forms. As Lewis says, 'The point of view is merely lexical and historical', and 'not an essay in higher linguistics', but this belies the many adventitious benefits that stem from his handling of the resources at his command. His purpose is to give us 'an aid to more accurate reading' and to throw light 'on ideas and sentiments'.