Hepatitis viruses research started more than fifty years ago. The names of hepatitis A and hepatitis B were introduced in 1947 when it became clear that there were two types of hepatitis that were transmitted either enterically or parenterally. It became apparent in the 1970's that there were additional hepatitis viruses distinct from hepatitis A and hepatitis B, and thus, the term non-A, non-B hepatitis was introduced. The non-A, non-B hepatitis was further divided into post-transfusion non-A, non-B hepatitis and enterically-transmitted non-A, non-B hepatitis in the 1980's. By the end of the...