Rheumatology explores systemic inflammatory and autoimmune processes that commonly involve multiple organ systems beyond joints. Volume 1 examines how rheumatic disease intersects with the nervous, cardiovascular, respiratory and endocrine systems and how systemic inflammation alters physiology. Chapters discuss clinical patterns, relevant investigations, and the principles linking immune dysregulation to organ-specific manifestations. Practical diagnostic pathways and red-flag indicators support early recognition and interdisciplinary referral. The text integrates pharmacology and monitoring considerations for immunomodulatory therapies that affect these systems. It’s written for residents and clinicians aiming to understand the multisystem nature of rheumatic disease.