Having a roof over our heads means more than to be dry. It includes our most basic ideas of comfort, well being and security. Man operates comfortably within quite narrow tem perature limits only, about 1 8 -3 0 ° C and, historically, his growing inventiveness in shelter must have gone hand in hand with extending his ter ritory and the things he could do. Obviously, shelter is sharply influenced by climate and the materials to hand. Desert mud dwellings with thick walls and small windows, lightweight jungle leaf huts, insulating log cabins, igloos, all are responding to climate and place.