This is a research by a group of German authors. Including some in which time itself had something to do with this test centers. These centers tested many of the aircraft from 1920 until the end of World War II.
The book starts talking about the secret testing in cooperation with the Russians in 1920-1930. The book covers the main test sites, including Johannisthal, Lipetsk, Rechlin, Travemunde, Tarnewitz Peenemunde and West. Other less known locations including the earlier tests in Döberitz and Danzig are also covered.
The book contains a large collection of photographs and documents, many taken from hitherto unpublished sources. There are short lists of the aircraft are complete, with details such as numbers, characters and types of engines. There are similar lists of personnel and test equipment.