The guide describes modern ideas about the morphology and physiology of the kidneys, the mechanisms of development and progression of nephropathies, and methods for studying nephrological patients. The leading clinical syndromes (nephrotic syndrome, renal hypertension, acute and chronic renal failure) and the main kidney diseases - glomerulonephritis, pyelonephritis, nephrolithiasis, amyloidosis, kidney damage in systemic, metabolic, infectious diseases and tumors are presented.