In the recent economic history, work sharing has been a subject for discussion and thought at three distinct periods: during the Great Depression of the thirties, at the time of the late seventies' recession, and since the beginning of the nineties. These three periods are characterized, not only by a high unemployment rate, but also, and maybe0501nly, by a very high level of pessimism towards the possibility of an eventual employment pickup that would de strong enough to integrate both those who lost their jobs, and those freshly arrived arrived on the job market. Is work sharing the solution to this problem ? This paper summarizes what we already know on the impact onto employment of regulating work hours, shows, using a concrete case, the difficulty of reducing work hours to stabilize employment while0501ntaining the same level of productivity, and concludes with a few warning remarks on the expectations that arise when work sharing is viewed as a solution to the unemployment problem.