How can architecture create a pleasant indoor climate using construction techniques and as little technology as possible? Researchers from four different departments at the Technical University of Munich joined forces with the engineering firm Transsolar Energietechnik to explore integral strategies for simple, energy-efficient construction. The architecture firm Florian Nagler Architekten implemented the plans developed by the TUM project for three prototype buildings made of solid wood, masonry and lightweight concrete in monolithic construction. Using these apartment buildings as examples, the guide vividly elucidates the six core principles of simple construction.