A relatively new book about the incredible legacy of physical models used for designing and understanding of lightweight structures has been published by Spector Books (part summary below from their website).
In the 1950s, Frei Otto’s tent structures left their mark on the horticultural shows of the new Bonn Republic; together with Behnisch & Partner he created the roof landscape for the Munich Olympic Games in 1972. The innovative potential in his work is based on the interdisciplinarity of a mode of thinking that took in architecture, technology, art, science, and society. He saw nature as a model and tried throughout his life to harness it for the sake of architecture and civil engineering — and thus also for the future. The Frei-Otto Archive features a large number of experimental models. The book will come out in two editions (German and English) and will be the first time Frei Otto’s models have appeared in print.
For a summary and to purchase a copy see this LINK