War of the Invisible Ones. Island of Fogs

The years before World War II are often called the era of intelligence services’ struggle. Professor Burago’s breakthrough could not leave secret-hunters indifferent. After all, the scientist’s research made it possible to keep ships, submarines, and aircraft hidden from prying eyes! Alexander Naydenov and Pavel Zhitkov have to fight the ruthless Nazis, who are not stopping at anything…
A famous novel by an author of many Soviet bestsellers that the whole country was reading half a century ago.