Pathophysiology (Theory) provides a clear and systematic understanding of the mechanisms underlying disease processes. This book bridges basic sciences and clinical practice by explaining how normal physiological functions are altered in various pathological conditions. Written in a student-friendly manner, it covers fundamental concepts, disease progression, clinical manifestations, and key correlations essential for healthcare and pharmacy students. The content is organized logically with simplified explanations, diagrams, and relevant examples to enhance comprehension and retention. It serves as a strong foundation for understanding diagnosis, pharmacological management, and clinical decision-making, making it an essential reference for undergraduate and postgraduate learners in medical, pharmacy, and allied health sciences.