Hepatocellular carcinoma (HCC) is the most common disease in the primary malignant tumour of the liver. It is considered that the therapy for HCC is very troublesome because most of the HCC occur from the injured liver such as chronic hepatitis or cirrhosis. If the patients with HCC receive proper therapy for their stage of HCC and liver function, a long survival is expected. In this book, the up-to-date contents of aetiology, diagnosis techniques, and various kinds of therapies for HCC are described. This book is very helpful for the medical staff that takes care of the patients with HCC. The contents of this book include precise descriptions of the following: i) the aetiology and epidemiology of HCC, ii) the diagnosis technique of CT and MRI, and the indications and results of the treatments, ie: iii) radio-frequency ablation, iv) molecular-targeted therapy, v) surgical resection, vi) transplantation, vii) trans-arterial chemo-embolisation, and radiotherapy. In addition, viii) proton beam therapy is introduced, which is a less invasive therapy for localised HCC.