To whatever extent manufacturing facilities are automated, they still need humans with supreme authority over production management even in the new century. As sophistication in manufacturing systems increases, however, renewed operational and organizational issues have arisen associated with human resource management. This paper intends to give an overview of current topics and/or issues regarding the relationship between humans and machines in modernized manufacturing systems, and to provide a general idea on the challenges undertaken in an international joint research project developed under the IMS program for addressing human factors issues, based on a re-recognition of the significance of human roles in manufacturing activities.