In considering the subject of this Symposium I was somewhat encouraged by a reminder of my company's first memorandum of association, written back in 1946. It is: to send and receive signals, messages and communications to and from aircraft, dirigibles and all other vehicles propelled in the air. How far-sighted those solicitors and recently demobilised airmen must have been! For although it has been the brief privilege of but very few of my air traffic control colleagues to have worked a non-dirigible a few years ago, I cannot honestly feel certain that they seriously believed that the age of the airship would dawn again. (Or did they?)