An international manual is like a world cruise: a once-in-a-lifetime experience. All the more reason to consider carefully whether it is necessary. This can hardly be the case if previous research in the selected field has already been the subject of an earlier review-or even several competing surveys. On the other hand, more thorough study is necessary if the intensity and scope of research are increasing without comprehensive assessments. That was the situation in Western societies when work began on this project in the summer of 1998. It was then, too, that the challenges emerged: any...

An international manual is like a world cruise: a once-in-a-lifetime experience. All the more reason to consider carefully whether it is necessary. This can hardly be the case if previous research in the selected field has already been the subject of an earlier review-or even several competing surveys. On the other hand, more thorough study is necessary if the intensity and scope of research are increasing without comprehensive assessments. That was the situation in Western societies when work began on this project in the summer of 1998. It was then, too, that the challenges emerged: any...