The author has collected in this volume his papers and talks over the past 20 years on the subject of information theory. He identifies the underlying thread of his work--the idea that there is a valid analogy between Heisenberg's "Principle of Uncertainty" and certain aspects of information theory. Three of his papers then provide introductory information; the remaining nine deal with symbols, communication, meaning, questions and commands, understanding, information generators, and indeterminacy. At the end of each paper the author provides a postscript, commenting on the paper from the viewpoint of present knowledge. He provides in an appendix an explanatory survey of the terminology of information theory and a paper on structural information content and optical resolution. A list of references and a subject index are also provided. (JY)