Both public and private data sources were used, and data were confirmed by individual police agencies. During the study period, 17 officers were murdered by gun shot, 2 by bomb blasts, 1 by knife, and 1 by motor vehicle. A total of 94 officers were wounded -- 71 by gunshot, 3 by bomb. Junior, uniformed, unmarried, and male police officers were the predominate victims of these assaults. Rifles were the most frequently used weapons of assault. Offenders were predominantly male and young, and usually acted alone. Officers generally were killed or injured while in the company of others. Temporal characteristics of murders and woundings varied by jurisdiction. Finally, there was no evidence that murders and injuries from shootings and bomb blasts have been increasing over the 20-year study period. Appendixes provide additional research data. 10 tables, 12 figures, and 12 references.