In spite of the fact that the mankind uses radio waves, magnetic and electric forces everywhere, the structure basics of an electromagnetic field and its material carrier have not been found up to now. There are many gravitation theories that differ radically. We believe that the transmitting agent of electromagnetic, gravitational etc. influences is the ethereal medium. The visible space is filled with the ethereal medium. The ethereal medium consists of two types of particles that are of the same size, but opposite in sign. These particles are strongly attracted together forming a homogeneous space. The ethereal medium has a certain electromagnetic density and elasticity. In the ethereal medium linear, circular and other movements of physical bodies may exist infinitely long. An electromagnetic field is the consequence of torsion, twisting and shear deformations of the ethereal medium. Gravitational influence of one physical body on the other is realized by means of the ethereal medium establishing a gradient of the ether elastic pressure on a physical body. The book can be useful for physicists, astronomers and those interested in the universe basics.