Software refers to the complete set of processes, programs and routines linked with the operation of a computer system. It is utilized to develop non-physical tools to solve information-based issues. Software technology encompasses the programming languages, methods and tools that may be used in the development of software. Some examples of software are Google Docs, Directory Opus, MySQL, BIOS, MS Access, WinZip, etc. Theoretical computer science (TCS) is a branch of general computer science and mathematics that focuses on the mathematical aspects of computer science including the type theory, theory of computation and lambda calculus. It covers a wide range of topics such as parallel and distributed computation, automata theory, algorithms, information theory, data structures, quantum computation, computational complexity, and probabilistic computation. This book explores all the important aspects of software technology and theoretical computer science in the present day scenario. It elucidates new techniques and their applications in a multidisciplinary manner. This book is a resource guide for experts as well as students.