This comprehensive text Nephrology in Internal Medicine: Renal Function and Disorders serves as an essential and in-depth resource for medical practitioners, students, and specialists seeking a robust understanding of the renal system’s integral role within broader human physiology and pathology. The book is systematically structured to guide the reader from fundamental principles to complex clinical management, beginning with a detailed exploration of renal anatomy and physiology, which establishes the critical foundation for appreciating the organ’s sophisticated functions in filtration, homeostasis, and endocrine signaling. It then seamlessly transitions into the practical arts of diagnosis, meticulously outlining the diagnostic approaches in nephrology, including urinalysis, advanced imaging modalities, and the interpretation of key biomarkers and renal biopsy, equipping the clinician with the necessary tools for accurate assessment. The core of the work addresses the spectrum of kidney diseases, dedicating substantial sections to the pathophysiology, etiology, and evidence-based management of acute kidney injury and chronic kidney disease, framing them as both independent entities and frequent complications of systemic illness. This progression naturally leads to a thorough examination of end-stage renal disease and the intricacies of renal replacement therapy, encompassing dialysis modalities and transplantation. Further chapters delve into specific disease categories, providing nuanced insights into glomerular disorders, tubulointerstitial diseases, and vascular diseases of the kidney, each dissected to reveal their unique mechanisms and clinical presentations. The book also masterfully tackles the complex challenges of electrolyte and acid-base disorders, offering a clear physiological framework for diagnosis and correction, and dedicates attention to infections of the kidney and urinary tract.