This paper details the authors' selection, design, and use of a life history calendar (LHC) to collect retrospective life course data. A sample of nine hundred 23-year-olds, originally interviewed in 1980, were asked about the incidence and timing of various life events in the nine years since their 15th birthday. The accuracy of the LHC retrospective data can be tested by comparing the 1980 reports about current activites with the 1985 LHC retrospective reports about those same activities during the 1980 interview month. The following aspects of the LHC are described: (a) the concept, uses, and advantages of the LHC, (b) the time units and domains used, (c) the mode of recording the responses and the decisions and problems involved, (d) interviewer training, and (e) coding. The following results attest to the accuracy of the LHC retrospective data: (a) only four of the calendars had missing data in any month; (b) the data obtained in 1980 about current work, school attendance, marriage, and children showed a remarkable correspondence to the retrospective 1985 LHC reports of these events; (c) the interviewers were positive about the LHC's ability to increase respondent recall.