Viruses that produce tumors are defined as oncogenic viruses.These include Papovaviridae; Papillomavirus (some); Herpesviridae Lymphocryptovirus (Epstein-Barr virus) ; Hepadnavirus; Hepatitis B virus(HBV); Adenoviridae; Poxviridae; Human T-cell leukemia virus (HTLV-1; HTLV-2);Sarcoma viruses of cats, chickens, rodents;Mammary tumor virus of mice and Feline leukemia virus (FeLV).This new book presents the latest research in this field.