Elements of Information Theory, Second Edition, covers the standard topics of information theory, such as entropy, data compression, channel capacity, rate distortion, multi-user theory and hypothesis testing. It presents applications to communications, statistics, complexity theory, and investment. Chapters 1-9 cover the asymptotic equipartition property, data compression and channel capacity culminating in the capacity of the Gaussian channel. Chapters 10-17 include rate distortion, the method of types, Kolmogorov complexity, network information theory, universal source coding and portfolio theory. The first edition of this book is the most successful book on Information Theory on the market today. Adoptions have remained strong since the book's publication in 1991.