These reprints, dating from 1950, present first three talks from BBC's Third Programme, intended to be a "popular" introduction to information and communication theories. The more technical papers in the second section try to relate these ideas to human communication.
The author makes clear the differences between the two theories, and delineates three types of information: structural (Gabor's logons), metrical (Fisher's metrons), and probabalistic (Shannon's "bits"). He then tries to construct a mechanistic theory of "meaning," while valiantly avoiding behavioral language. The resulting models, even when strained at the seams, make a rather poor fit, and perhaps reveal more about MacKay's ingenuity than they do about human communication. His geometrical vector model for the semantic load is particularly unsuitable, and pragmatically presents more problems than it solves.
Possibly MacKay, comfortable with his sender-channel-receiver model, errs in hypothesizing that the simplest explanation (complicated enough) is the most likely, when trying to