This book titled The ICU Book on Renal Replacement Therapy, compiled by a group of nephrologists and intensivists, consolidates the knowledge and expertise of both specialties into a single resource, thereby expanding the intensivists understanding of the bedside management of critically ill patients requiring renal support. It is an effort to provide a clinical guide to bridge the gap between the theoretical concepts of renal physiology and the practical applications of RRT in the intensive care unit (ICU). The book clearly explains the underlying principles of RRT, including diffusion, convection, ultrafiltration, and adsorption. It also details the various modalities such as prolonged intermittent RRT, continuous RRT, and peritoneal dialysis. This allows intensivists to understand the mechanisms and select the most appropriate therapy suited to the patients condition. It provides evidence-based guidance on critical decisions, such as indications for initiation, choice of modality, dosing, and anticoagulation, and also covers troubleshooting scenarios frequently encountered in the ICU. This will empower intensivists to make informed decisions and adapt RRT prescriptions as needed. The book also includes few new additions keeping in pace with new technological advancements like hemadsorption, plasmapheresis, and extracorporeal carbon dioxide removal. The highlight of this edition is the last chapter which is a series of cases. Each case is followed by an expert commentary by one of the pioneers in the field, Dr Valentine Lobo. The multiple-choice questions at the end of the chapters are designed to help students review and assess their comprehension of the chapters content.