Using the 1939 Register: Recording the UK population before the war

The preparations had been made well in advance. Now Britain was
at war, and as the uniformed army prepared to face the enemy, a
civilian army was mobilised at home. National Registration
Officers, registrars, and 65,000 enumerators set about the huge
task of registering every man, woman and child in a single
weekend. It all went remarkably smoothly. This is the story of
the 1939 Register for England and Wales, how it was taken, and
what happened next.