Comprehensive, rigorous introduction to work of Shannon, McMillan, Feinstein and Khinchin. Translated by R. A. Silverman and M. D. Friedman.
Here's a sample of other books in this Dover category
Information Theory by Robert B. Ash Analysis of channel models and proof of coding theorems; study of specific coding systems; and study of statistical properties of information sources. Sixty problems, with solutions. Advanced undergraduate to graduate level.
Information Theory and Statistics by Solomon Kullback Highly useful text studies logarithmic measures of information and their application to testing statistical hypotheses. Includes numerous worked examples and problems. References. Glossary. Appendix. 1968 2nd, revised edition.
Stochastic Processes and Filtering Theory by Andrew H. Jazwinski This unified treatment presents material previously available only in journals, and in terms accessible to engineering students. Although theory is emphasized, it discusses numerous practical applications as well. 1970 edition.