This Guide commences with a discussion of domain analysis@ followed by component assessment and concludes with the role of a reuse library. Section 2.0 defines domain analysis@ and describes the principal products of such an analysis. Discussion of various approaches and techniques documented in the literature is then provided. Examples of current aerospace applications domain analysis are the Common Ada Missile Parts (CAMP) and the Naval Training Systems Center Reuse Initiative projects. Criteria to be considered for domain analysis are then presented. Section 3.0 explains component assessment for reuse and provides criteria that could be used for such an assessment. To achieve significant productivity gains with reuse@ the traditional concept of components as source code must be expanded to include components of many types such as specificaions@requirements@ designs@ data sets@ and test sets. The component assessment criteria of section 3.0 are divided into three categories: domain assessment@ reuse assessment@ and software assessment criteria. Finally@ as presented in section 4.0@ the assessment criteria specified during the domain analysis process must be captured and stored in a reuse library where they are readily accessible to both the component developers and the component assessors. The reuse library stores information about the domain and provides tools to facilitate its use. The role of the library with respect to component assessment is described to provide a complete picture of the reuse process from the assessment perspective.