1 Papillomaviruses: General Description, Taxonomy, and Classification.- I. Introduction.- II. Properties of the Virions.- A. Particle Structure and Protein Composition.- B. Nucleic Acid.- III. Biological Properties.- A. Characteristics of the Benign Tumors.- B. Immune Response of the Host.- C. Malignant ConversionGeneral Aspects.- IV. Classification and Nomenclature.- V. Description of Virus Types.- A. Human Papillomaviruses.- B. Bovine Papillomaviruses.- C. Other Papillomaviruses from Animals.- VI. Evolutionary Aspects.- A. Papillomaviruses and Miopapovaviruses.- B. Evolution of Papillomaviruses.- C. Papillomaviruses from Epidermodysplasia Verruciformis.- D. Reservoir of Papillomaviruses.- References.- 2 Animal Papillomas: Historical Perspectives.- I. Canine Oral Papillomatosis.- II. Shope Rabbit Papilloma.- III. Equine Papillomatosis.- IV. Bovine Papillomatosis.- V. Papillomatosis in Sheep.- VI. Oral Papillomatosis of Rabbits.- VII. Deer Fibromatosis.- VIII. European Elk Papillomaviruses.- IX. Viral Papillomatosis in Other Animals.- References.- 3 Organization and Expression of Papillomavirus Genomes.- I. Introduction.- II. General Properties of Papillomavirus Genomes.- III. The Genome of BPV-1.- A. Organization of the E (Transforming)-Region.- B. Organization of the L-Region.- C. The Noncoding Region.- D. Transcriptional Signals.- E. The Origin of DNA Replication.- IV. Comparative Anatomy of Papillomavirus Genomes.- A. Features of the HPV-la Genome.- B. Features of the HPV-6b Genome.- C. Features of the CRPV Genome.- D. Features of Other Papillomavirus Genomes.- V. Predicted Functions of Papillomavirus Proteins.- VI. Transcriptional Organization of Papillomavirus Genomes.- A. RNAs Expressed in Rodent Cells Transformed by BPV-1.- B. mRNAs Transcribed in Virus-Producing BPV-1-Induced Fibropapillomas.- C. The Transcription Map of the BPV-1 Genome Is Incomplete.- D. Transcriptional Organization of the CRPV Genome.- E. Common Features between BPV-1 and CRPV TranscriplÓ'