Future large-scale software development projects will require engineering support for a diverse range of software quality attributes, such as privacy and openness. It is not feasible to create one monolithic methodology to support all possible quality attributes. Instead, we expect AOSE methodologies to be created and reused in a modular way. A modular approach enables developers to build custom project-specific methodologies from AOSE features in the same way applications are built from reusable off-the-shelf components. In this paper, we provide a conceptual framework for creating and reusing modular methodologies. This conceptual framework is based on the concept of an AOSE feature, which performs one or more development activities, such as analysis, and addresses one or more quality attributes, such as privacy. An AOSE feature encapsulates software engineering techniques, models, supporting CASE tools and development knowledge such as design patterns. We illustrate the applicabili...