Because of the many deficiencies and inconsistencies in statewide data on automobile theft, this study focused on a single geographic area for the early history of auto theft (1916-1952). The Los Angeles Police Department began recording auto thefts in 1916, some 14 years before most other localities and the Uniform Crime Reports. This study was undertaken in the belief that the changing levels of auto theft, measured over time, should provide a useful indicator of the changing cycles of criminality. The data show a rapid increase in thefts in the early 1920's, followed by an extended period of continuity until just after World War II. This second phase is distinguished by approximately 35 years of continuous annual increases in auto theft, with only minor lulls. Patterns for burglary and robbery in Los Angeles followed this same pattern. Data indicate that most car thieves did not steal cars to commit other crimes or to profit from a resale or from the parts. The car thief most often wanted short-term transportation or a brief "joyride." The study concludes that the mid-century shift from a cyclic pattern of auto theft to a pattern of continuous annual increases requires an analysis that could elucidate crime patterns. 16 graphs, 8 tables.