The true history of aviation is not only a ceremonial chronicle of achievements and victories, but also a bitter chronicle of failures and disasters. People do not like to remember these defeats, these failed projects are consigned to oblivion - but without them, the history of aviation is emasculated and incomplete. Moreover, many developments had to be abandoned not because of their inconsistency, but because they were too ahead of their time. The heavy bomber "Svyatogor", high-altitude BOK aircraft, aircraft giants Tupolev and Kalinin, the first gyroplanes, the anti-tank attack aircraft "Pegasus" - this book covers in detail the most ambitious domestic aircraft projects, on which at one time great hopes were pinned, in which huge amounts of money were invested, time, human and production resources, which could have turned the entire history of aviation, but for various reasons (high cost, accident rate, intrigues of competitors, repression, etc.) remained on paper or were frozen at the stage of flight tests and prototypes, never claimed by the Air Force.