The liver is one of the organs that receives blood mostly from the systemic circulation. The liver is an important organ in which most metabolic events develop. The detoxification of toxins is also amongst the liver functions. In some cases, liver pathologies can be easily treated, and in some cases, it can lead to the end of life. Liver tumors, bacterial and viral infections, cirrhosis, and Wilson's disease are among the most common liver diseases. Liver cancers can be primary or secondary due to metastases from other organs. Patients with secondary liver tumors can even be diagnosed without a primary tumor diagnosis. Early diagnosis of liver diseases can increase treatment success. Physicians may encounter liver diseases throughout their professional life. Therefore, our book has been prepared for all physicians. The distinguished authors in our book wrote their chapters by combining their scientific knowledge with their experiences.