The daily lives of human being of any race, creed and region has the impact of languages, which allows us to express our emotions, desires, and queries to the people in the world around us. With the help of written and spoken language people can form lasting bonds with one another. As we know it is not possible to study all the languages in the world, solution to this problem is to use the automated machine translation techniques which permit us to translate one natural language to another. First recorded machine translation was done in 1954 by translating more than sixty Russian sentences into English. Followed different methods for translating natural language is came into existence namely Rule Based System, Example Based System, Statistical Machine Translation system, Neural Machine Translation system and Hybrid translation systems. This book aims a detailed study of these methods. Also, it discusses translation process, applications and challenges of machine translation in this book.