Robots in the 20th century have been valued mainly for their enhancement of productivity. According to Professor Ichiro Kato of Waseda University, 21st-century robots will be valued because they enhance amenity. The development of robot systems for health care, detailed in this special issue of Robotica, is an affirmation of this forecast.

Several factors have combined to cause this development, although economic factors are paramount. Industrialised countries, where robots are most likely to be used, face an ageing population-a result of lower birth rates, reduced infant mortality and increased life expectancy. This ‘ageing society' is expected to have enormous impact upon these countries’ health and social security systems which devote a large proportion of their resources to the care of older people.