Warfarin is one of the most commonly used anticoagulant drugs worldwide with a role in the treatment for a variety of conditions, such as atrial fibrillation, artificial heart valves, deep venous thrombosis, pulmonary embolism and antiphospholipid syndrome. Although effective as an anticoagulant drug, care must be taken in warfarin administration as it interacts with many commonly used medications and some foodstuffs. This book presents current research in the study and uses of warfarin.