Numerous methodologies for developing agent-based systems have been proposed in the literature. This proliferation creates a challenge to practitioners who need to select a methodology to adopt. This situation is analogous to that of object-oriented methodologies and notations pre-UML, and we argue that the time is ripe to begin the development of a next generation agent-oriented software engineering (AOSE) methodology, leading ultimately towards a unified AOSE methodology. This paper proposes process and models for a next generation AOSE methodology. Our proposal is based on a comparative analysis of seven prominent AOSE methodologies, which identified strengths, weaknesses, commonalities and differences.