THE purpose of this communication is to explain, in terms of the theory of information, the implications of the Zipf distribution of word frequencies1. The distribution is formally identical with the Pareto income and Willis taxonomic distributions, but the present discussion is restricted to word frequencies. The discussion resembles that of Mandelbrot2 but is simpler. The discussion by Parker-Rhodes and Joyce3 also resembles Mandelbrot's, but is fallacious.