What is hidden behind the mysterious inventions of Nikola Tesla? How was the great inventor connected with the mystery of the disappearance of the destroyer Eldridge during the Philadelphia experiment? What kind of mysterious experiments were carried out by Nikola Tesla's followers at an abandoned Air Force base in Montauk? The author examines these and many other fascinating questions through the prism of the latest achievements of science and technology. The book is written in the form of a collection of popular essays - investigations of the dark spots in the biography of the outstanding electrical engineer and inventor Nikola Tesla. The book is intended for a wide range of readers interested in the secrets of military scientific research.