Designed as a comprehensive guide to the National Longitudinal Surveys of Labor Market Experience (NLS), this handbook is intended for two major categories of readers. For persons who wish to ascertain whether their research interests can be served by the NLS data, the handbook can provide the detailed description of the objectives of the surveys, the samples covered, and the types of information collected. The availability and cost of several NLS data files are also presented. For researchers who acquire the data files, the handbook performs the additional functions of describing the layout of the computer tapes, explaining the documentation, and presenting a number of caveats relating to the use of the data. All information is presented in the handbook under the following division titles: Structure and Development of the NLS Research Project; Sampling, Interviewing and Estimating Procedures; Description of the NLS Data; The Public-Use Tapes and the NLS Clearing House; Characteristics of NLS Data Files; and documentation. An extended bibliography is included, and sample pages from NLS documentation are appended. (BM)