This book's fourth edition was meticulously written in accordance with the new syllabus established by the Pharmacy Council of India (PCI) in accordance with ER-2020. This book is presented and published to satisfy the needs of first-year pharmacy diploma students (D Pharm). The book, which is written in clear, straightforward language, makes an effort to demystify and simplify the fundamental ideas for pharmacy students in order to ensure adequate knowledge of the subject and success on the State Board Examinations.