"Mastering English Grammar - The Complete Language Proficiency Handbook" by Jitendra Singh is a comprehensive guide aimed at enhancing language proficiency for learners of all levels. The book covers fundamental aspects of English grammar, such as the structure and types of sentences, parts of speech, and the use of tenses, as well as advanced topics like modal verbs, conditional sentences, and the intricacies of active and passive voice. With a focus on clarity, real-world examples, and an engaging writing style, this handbook serves as an essential resource for students, professionals, and anyone looking to improve their command of the English language. The author, Jitendra Singh, combines his extensive background in technology and education to present complex grammatical concepts in an accessible and enjoyable manner.