Internationally recognized mathematician, Ivan Niven's 6 th Edition of An Introduction to the Theory of Numbers continues to focus on number theory. The text expands on previous issues with more in-depth and enhanced treatment of the binomial theorem, techniques of numerical calculation and public key cryptography, as well as new outstanding set of problems. Chapters are easy to read with several new features and more information on techniques of numerical calculation, expanded treatment of the binomial theorem, and a section on public key cryptography.