Chemical composition of animal viruses, by M. Green. Virus architecture as determined by X-ray diffraction and electron microscopy, by C. F. T. Mattern. The replication of picornaviruses, by D. Baltimore. The genetic analysis of poliovirus, by P. D. Cooper. Myxoviruses, by C. Scholtissek, R. Drzeniek, and R. Rott. The reoviruses, by C. J. Gauntt and A. F. Graham. RNA tumor viruses, by J. P. Bader. Biochemistry of adenovirus infection, by H. S. Ginsberg. The biochemistry of poxvirus replication, by B. R. McAuslan. Herpesviruses, by B. Roizman. DNA-containing bacteriophage, by C. K. Mathews. Biochemistry of interferon, by H. B. Levy, S. Baron and C. E. Buckler.