The third in a series of annual documents designed to report estimates of transactional data on juvenile offenders, this report is based on data from more than 500,000 records, representing nearly one-third of all the cases processed in 1977 by the Nation's courts with juvenile jurisdiction. During 1977 the child population at risk (the number of young people for age 10 to the upper age of juvenile court jurisdiction, which varies from State to State) numbered 29,551,000. For the year 1977, this population produced an estimated 1,355,500 cases processed by courts with juvenile jurisdiction, or 45.9 cases per 1,000 child population at risk. This represents a decrease of 0.3 cases per 1,000 over 1976. The actual number of cases decreased by 41,300 (3.0 percent). Of all processed cases, over three-fourths involved males, a finding consistent with data from previous years. Female offenders, however, were found to be more likely to be charged with status offenses that were male offenders. In 1977, 46 percent of all offenses involving females were for status offenses; the comparable figure for males was only 16.3 percent. Racial frequencies remained almost identical to those reported in 1976. Compared with whites, minority members were found to processed differently, more likely to have had prior referrals, and detained more frequently. Furthermore, they were less likely to be charged with crimes against people, processed more often with a petition, and more likely to be institutionalized. In addition to reporting frequencies on relevant variables for 1977, this document examines trends between 1975 and 1977. For example, from 1975 to 1977, the following rate changes were found for referral: status offenses, a negative 18.2 percent; drug/alcohol offenses, a negative 16.9 percent; crimes against people, a negative 7.6 percent; crimes against property, a positive 12.3 percent; and other offenses, a positive 15.8 percent. Most of the document consists of tabular material, but an executive summary, an explanantion of the methods of processing the data, and a user's guide are also provided. (Author abstract modified)