This book delves into the various aspects of the renin-angiotensin-aldosterone system (RAAS) and its role in cardiovascular disorders. It explores the use of anti-hypertensive agents, with a focus on (ACE) angiotensin-converting enzyme inhibitors and angiotensin receptor blockers (ARBs). The chapters cover topics such as the preferred use of ACE inhibitors over ARBs in high-risk patients, the impact of these agents on insulin resistance, their role in acute heart failure and peripheral artery disease, and their immunomodulatory activity in hypertensive patients. Additionally, the book examines the role of ACE inhibitors and ARBs in COVID-19 patients and provides insights into recent trends in managing hypertension through RAAS inhibition. It serves as a valuable resource for researchers, clinicians, and healthcare professionals involved in the field of cardiovascular medicine.