The textbook has been meticulously crafted and designed for Roga Nidhan & Vikriti Vigyan Paper-1 as per the new syllabus prescribed by NCISM for the 2nd year B.A.M.S. course. It is the first of its kind as per the new syllabus, providing a comprehensive and detailed description of all concepts of diseases from both Ayurvedic and modern science in a clear and concise English language. Furthermore, the book covers newer topics such as Nityasamshleshita dosha/Paricchedita dosha, Digital health and Artificial intelligence in the context of Roganidana, Sathmya and Asathmya, NAMASTE (National AYUSH Morbidity and Standardized Terminologies Electronic Portal) portal classification and terminology of diseases, and the scope of screening and triage, all of which are explained in great detail. The inclusion of important references from Charaka, Sushruta, Ashtanga Hrudaya/Sangraha, Madhava Nidana, Yoga Ratnakar, Bhavaprakash, Dalhana, Videha, Indu Tika, and other sources make this book a valuable resource for students. Additionally, complicated and confusing topics, conditions, and disorders are elaborately described and explained, aiding in the understanding of the subject matter for both undergraduate and postgraduate students. The book also provides a tabulation flowchart that briefly describes the differential diagnosis and principle of diagnosis of all pathological conditions, making it easier to understand and memorize important facts about the disease. Furthermore, a special question bank and MCQ are included in the book to enhance the reader's understanding of the subject.