Black door. The last experiment

The author of the book in 1970-1980. I had to work in the AYU commission (abnormal phenomena) of the State Hydromet and in a similar commission under the geographical society of the USSR. A lot of actual material of a very sensational nature, however, has passed through his hands, but inaccessible to the bulk of citizens for censorship reasons. Then the idea arose to publish part of it under the guise of a fantastic novel, which would combine real events with a fantastic plot.
As for people acting in the novel, most of them have real prototypes, by the will of the author participating in fantastic events. Genuine, adjusted to a fantastic plot, and many events described in the novel.
You hold in your hands the third book out of four