The document reports findings from a multiple jobholder survey. About 3.9 million workers (4.7% of all employed persons) held two or more jobs in May 1975. The multiple jobholding rate for men (5.8%) was higher than the rate for women (2.9%). Over half of the moonlighters held two nonagricultural wage or salary jobs. The incidence of multiple jobholding varied according to age, sex, and marital status. The number of female multiple jobholders increased during 1970-75 in industry and occupation of primary job. Multiple jobholding rates for male teachers below the college level was higher than for any other male occupation (16%). The larger proportion of male moonlighters had second jobs as farmers or professionals (17% each). Agriculture plays a much larger role in multiple jobholding than in the general labor market. A review of the kinds of secondary jobs held by moonlighters as related to the job desires of the unemployed suggests that very few of the unemployed would take the jobs held by moonlighters. About 35% of multiple jobholders held second jobs to meet regular expenses (one-half of black moonlighters and one-third of white moonlighters). Definitions of basic labor force concepts are given. Supplementary tables support the analysis. (Author/EC)