The monograph proposes a new approach to the study of the Tunguska fall of 1908. The phenomenon is considered within the framework of the problem of solar-terrestrial relations. The results of a detailed information analysis of eyewitness reports of the phenomenon with the geological and geophysical situation of the Tunguska phenomenon observation area are presented. Plasmoid model of Tunguska bolide and possibility of phenomenon interpretation as a population of plasma formations of solar origin are considered.