With the increase in the trend toward intervention procedures for hepatic lesions and operative management with regional hepatectomies and liver transplantation, there is an upcoming generation of radiologists as well as gastro-hepatologists who are specially trained to do these procedures. The basic anatomy of the liver in the form of Couinaud segments is well known to radiologists. With the advancement in imaging techniques like multidetector computed tomography (MDCT) and magnetic resonance cholangiopancreatography (MRCP), knowledge about the complex anatomy of the biliary tract, vascular supply, and their variations is also indispensable. In this chapter, we shall form a systematic approach to the anatomy and variations of the biliary tree and vascular structures in the liver and learn more about the clinically significant variations which make us alter the course of operative management for the benefit of the patient.