This book covers major knowledge and recent advance regarding portal vein thrombosis. Portal vein thrombosis, a potentially life-threatening vascular disorder of the liver, refers to the development of thrombosis within main portal vein trunk and intrahepatic portal vein branches with or without splenic and mesenteric veins. In patients with acute portal vein thrombosis, if a thrombus extends into the mesenteric veins, there is a risk of intestinal ischemia and necrosis; in patients with chronic portal vein thrombosis, portal hypertension and its complications develop. The book includes chapters on the topics of epidemiology, risk factors, diagnosis, and prognostic impact, pharmacological, interventional with surgical treatment of this disease. Concepts of early diagnosis of portal vein thrombosis and extensive assessment of its severity are fully introduced. The book is beneficial for physicians to establish standard treatment strategy, for researchers to launch creative clinical and experimental studies.