What Professor Sundarapandian with his indepth knowledge and rich and long experience strives to do is to make the concepts very clear and compre- hensible to the students by his lucid presentation and illustrative approach. The book analyses various types of random processes, spectral density functions and their applications to linear systems. Besides, it deals with the basics of queueing theory with a clear exposition of the five important queueing models. The text gives a detailed description of such topics as random variables, standard probability distribution, central limit theorem, random processes and spectral theory. The text is profusely illustrated with examples and diagrams so as to make this rigorous subject more understandable to the students.