The aim of this book, part of the European Society of Intensive Care Medicine (ESICM) textbook series and designed by the NEXT Committee of the European Society of Intensive Care Medicine, is to provide the readers with a unique review of the main syndromes in Intensive Care Medicine by means of a collection of clinical cases. The book is structured in six sections (severe infections and sepsis, respiratory medicine, cardiovascular medicine, neurocritical care and severe trauma, severe endocrine and metabolic disorders, and severe inflammatory disorders), that allow the reader to focus on a specific area. Each section begins with an “introductory chapter” to maintain cohesion. Within each section, every chapter corresponds to a clinical case covering different aspects of a relevant disease. All the chapters have a uniform design: introduction/background, case presentation, investigations, differential diagnosis, treatment, evolution, outcome and follow-up, and discussion. The target audience of this work includes university students, fellows of intensive care medicine, critical care and emergency medicine residents, and experienced physicians aiming to review the most relevant syndromes of the specialty.