The book also presents important basic concepts on Brownian motion process, a shastic process of historic importance. It covers its few extensions and variations, such as Brownian bridge, geometric Brownian motion process, which have applications in finance, sk markets, inventory etc. The book is designed primarily to serve as a textbook for a one semester introductory course in shastic processes, in a post-graduate program, such as Statistics, Mathematics, Data Science and Finance. It can also be used for relevant courses in other disciplines. Additionally, it provides sufficient background material for studying inference in shastic processes. The book thus fulfils the need of a concise but clear and student-friendly introduction to various types of shastic processes.