The objective of the workshops associated with ER 2001, the 20th International Con- rence on Conceptual Modeling, was to give participants the opportunity to present and discuss emerging hot topics, thus adding new perspectives to conceptual modeling. This, the 20th ER conference, the ?rst of the 21st century, was also the ?rst one in Japan. The conference was held on November 27-30, 2001 at Yokohama National University with 192 participants from 31 countries. ER 2001 encompasses the entire spectrum of c- ceptual modeling, from theoretical aspects to implementations, including fundamentals, applications, and software engineering. In particular, ER 2001 emphasized e-business and reengineering. To meet this objective, we selected the following four topics and planned four international workshops: – International Workshop on Conceptual Modeling of Human/Organizational/Social Aspects of Manufacturing Activities (HUMACS 2001) Manufacturing enterprises have to confront a host of demands. The competitive climate, enhanced by communication and knowledge sharing, will require incr- singly rapid responses to market forces. Customer demands for higher quality, better services, and lower cost will force manufacturers to reach new levels of ?exibility and adaptability. Sophisticated customers will demand products customized to meet their needs. Industries have so far sought to cope with these challenges primarily through advances in traditional capital by installing more powerful hardware and software technology. Attention to the role of humans combined with organizational and social schemes in manufacturing has only been marginal. The workshop HUMACS 2001 aimed to challenge the relevance of this last point.