Acute and chronic hepatitis and hepatitis-related diseases such as liver failure, liver cirrhosis and hepatocellular carcinoma are among the most important causes for disabilities and death. Hepatocellular injury is due to a variety of agents including viruses, toxins, radiation, injury and drugs but also bacteria, parasites and autoimmune reactions. This volume reviews today’s knowledge about hepatitis with emphasis on comparative aspects between hepatitis in humans and animals, but also between different etiological agents. This particular viewpoint makes the book relevant for scientists from both human and veterinary medicine, gastroenterologists, pathologists, virologists and students of human and veterinary medicine.