Kidney diseases (or renal diseases) are a group of disorders characterized by damage to or disease of the kidney that affects the ability of the kidney to filter fluid and waste from the blood. These diseases can be classified into two categories, namely, nephritis and nephrosis. Nephritis is a condition in which there is inflammation in the kidney. There are several types of nephritis based on the site of the inflammation and it can lead to nephritic syndrome. Nephrosis is a condition without any inflammation in the kidney which can cause nephrotic syndrome. There are several causes of kidney diseases including accumulation of immunoglobulin A antibodies in the glomerulus, long term exposure to lead and its salts, long-term usage of analgesics, and administration of chemotherapy agents in the body. The diagnosis of kidney diseases involves a physical examination, and tests such as urine tests and renal ultrasonography. The topics covered in this extensive book deal with the core aspects of kidney diseases. It consists of contributions made by international experts. This book will serve as a valuable source of reference for graduate and post graduate students.