Blue links lead to the fully translated html versions of the page, purplelinks lead to pages whose start pages (as well as introductions and tables of contents at least) are already set up, green links lead to extern sites, grey means that no file is available yet).
/Notes in this color and between two / are from the operator of the German mirror site and translator/.
It is difficult to indicate other invention that would turn to be more vital for the present technical level of our civilisation, than the invention of airplane. After all, due to airplane for example the trip between Europe and other continents shortens from the level of several months to the level of several hours. It is also airplane that allows supply fat e.g. ill people to hospitals, medicine to ill people, while letters and parcels to healthy ones. But in spite of its significance, before airplane managed to enter permanently the pool of technical accomplishments of our civilisation, it needed to be independently invented in three different countries by people who mutually did NOT know about existence of other such inventors. This web page explains that the reason for such its fate was the lack of required level of morality in communities in which inventors of airplane were acting.