In the last twenty years, critical care medicine has been established as a specialty with its own therapies and procedures, with significant implications for clinical nephrology regarding severe acute renal failure. This typically multi-factorial condition is today predominantly seen in intensive care units. The complex knowledge and skills necessary to handle it have resulted in a field called Critical Care Nephrology, where nephrologist and intensivist either work side by side or have formally acquired expertise and training in both specialties. Extracorporeal renal replacement therapies, although originally used to treat end-stage renal disease patients, rapidly gained importance for acute patients. This has had far-reaching implications for the initiation and possible role of blood purification in the management of critically ill patients, widening the scope of interaction between the nephrologist and the intensivist. Experts in the field have contributed to the present book, providing a comprehensive review of the different blood purification techniques relevant in the intensive care unit in the case of multiple organ failure. The resulting mix of established knowledge and recent results from both clinical trials and basic research constitutes a valuable tool for all professionals involved in the care of the critically ill patient.