New working time arrangement are becoming still more abundant partly due to globalization (the 24-hours global economy with around-the-clock communication and transport of gods and services) and increasing demands for productivity and quality both in private and public sectors. The new working time arrangements are associated both with company -based flexibility, referring to the needs of employers to modify, extend or reduce work hours according to production needs, and with individual flexibility that provides more influence over own work schedule for the employees but also contains the risk of over-commitment. I all Nordic countries an increasing public debate on stress, mental health problems and conflicts between work and private life have emerged during the last decade. To some extent the public debate seems to be governed more by beliefs than by knowledge and scientific evidence. The knowledge in this field is far from complete, but in some areas research has provided good knowledge, and several ongoing research projects will provide new and important knowledge the coming years. The present report - being the result of a Nordic expert group - provides an excellent review of the current international scientific knowledge with regard to direct social consequences (mental well-being, stress and work-life balance) of long and irregular working hours and employee influence on working hours. Furthermore, the labour market development in the Nordic countries is presented in relation to new working time arrangements. The report provides a well-structured insight in the social consequences of new working time arrangements. I am convinced that decision makers, working environment professionals, and researchers will gain a lot by reading the report.   Monday, 24 September 2007     Otto Melchior Poulsen Research Director National Research Centre for the Working Environment