This report summarizes and documents the major technical aspects of the High School and Beyond (HS&B) third follow-up survey conducted during the spring and summer of 1986. Young persons who, either as sophomores or as seniors, had participated in the base year survey in 1980 were contracted for the fourth time in 1984 and asked to complete questionnaires detailing their activities since leaving high school. The senior and sophomore cohort samples for the third follow-up survey were the same as those used for the first and second follow-ups. Survey activities were initiated for all sample members. Mail-back questionnaires were the basic method of data collection and approximately 26,800 packets of survey materials were mailed. Telephone and personal interviews were conducted for those not responding by mail. Approximately 66% of both samples mailed back completed questionnaires; 5% of the seniors and 6% of the sophomores were interviewed in person; and 16% of the seniors and 19% of the sophomores were interviewed by telephone. In addition, this report includes information on the survey forms employed as well as sample design and implementation, and the data collection and data processing procedures used in the HS&B base year study and the three follow-up surveys. (Sample questionnaire and correspondence are included.) (KSA)