Forgive my starting with so inelegant a quotation, used earlier this year at a meeting of computer professionals by a speaker who was criticizing the ‘incestuous’ nature of the discussions in their closed circle: I am sure that it does not apply to the present meeting. But it does apply to meetings of many kinds of technical specialists where no opportunities are given for people outside the family circle to listen, to criticize, and to present their own viewpoints. The quotation also raises important policy issues, to which I shall return later.