What is the theme in The Hidden Dimension by Edward T. Hall?

From the earliest caveman through contemporary man, human existence and activity has always involved man's perception of his place in space, his use of space, and his perception of spatial needs for comfort and security. The base of space experience initially comes from vision, hearing, smell, and touch, and when man is able to synthesize these experiences, he develops a perception of his spatial environment which is unique, because no two individuals perceive things in exactly the same way. These unique perceptions are then molded into commonality by the patterns of language and culture, so that groups of people develop common spatial needs and requirements. The diverse ways in which cultural groups perceive their space translate into a variety of structures and extensions of structures which can be easily observed and understood, with appropriate study and research.