Any formal language which consists of a set of instructions and is capable of producing different types of output is defined as a programming language. These are utilized in programming computers for the implementation of various algorithms. The three major components which describe a programming language are semantics, syntax and type systems. The surface of any programming language is known as syntax. It is textual in nature and makes use of sequences of words, numbers and punctuations. Semantics are divided into static semantics and dynamic semantics. Type systems are responsible for classification of different types of values and expression into types. Programming languages is an upcoming field that has undergone rapid development over the past few decades. This book is a valuable compilation of topics, ranging from the basic to the most complex theories and principles in the field of programming languages. It presents this complex subject in the most comprehensible and easy to understand language. This book will serve as a valuable source of knowledge for those interested in this field.