The subject of Cryptography and Network Security is assuming more importance evident from the fact that this paper is slowly turning out to be a core paper after having been a popular elective for quite some time. Forouzan?s title treats the subject in a lucid manner explaining tough concepts through simple schematic diagrams and easy to understand language. The text also gives an account of mathematical preliminaries needed for understanding Cryptography. Key Features: Lays emphasis on important concepts like- Loading, regulation, dependent and independent sources, fundamental linear circuit analysis laws and theorems. The chapters 'Essential Basics' and 'Semiconductor Physics' for ready reference. The theory is