This document was prepared to be used by those interested in a ready reference for the design features and accomplishments of Add Health (the National Longitudinal Study of Adolescent Health). It provides a summary of features incorporated in the first fifteen years of completed work on the Add Health Study. The reader is referred to our web site (www.cpc.unc.edu/addhealth) for additional information, and for availability of data. Parts of this document may be incorporated into other documents for grant applications, papers for publication, or public presentations, without further permission. This document will be useful for those planning to use existing Add Health data.