This particular treat discusses field of tension and refers to the work of Piet Zwart and Cheryl A. Brzezinski. The article discusses how field of tension is used to create a taut relationship between the type, design elements, and the edges of the paper. The importance of field of tension is that even though there are very harsh, angular lines in the composition there is always a sense of balance in the composition as a whole. An example of this is mentioned in Zwart's use of the red arrow and in Brzezinski's use of type in negative space. Each composition is divided into zones but are threaded together with opposing design elements like using dark elements on a light background and vice versa.
I can already foresee this technique being applied to our books:)