The Theory of Environment: An Outline of the History of the Idea of Milieu and Its Present Status (1918) is a book written by Armin Hajman Koller. This book explores the concept of ""milieu"" or environment and its historical development as a theoretical concept. Koller traces the origins of the idea of environment from ancient Greek philosophy to modern times, examining how it has been understood and applied in various fields such as biology, psychology,...