Technical aspects of the first followup survey for the National Education Longitudinal Study of 1988 (NELS:88) are documented and summarized. Some information overlaps materials in the users' manuals for this followup, such as the overview and general descriptions of data collection, sampling, weighting, variance estimation, nonresponse patterns, and discussions of data control and processing. Unique to this report are: (1) psychometric documentation of the NELS:88 first followup tests; (2) documentation of the confidentiality and deductive disclosure analyses conducted with first followup data; (3) the detailed report on the base year ineligibles study; (4) expanded standard error/design effects tables; (5) samples of district contact letters and permission forms; (6) documentation of the update of addresses for the High School and Beyond Study; (7) content abstracts of publications about the NELS:88; (8) Spanish language survey instrumentation; and (9) a glossary of study terms. Sixteen figures and 26 tables present followup data and statistical information, and 11 appendixes contain supplemental and detailed information about methodology. (SLD)