This bookdescribes the main aspects of radio propagation due to different natural and manmade phenomena occurring in ionospheric plasma. It discusses the possibility of stable radio communication links based on local scattering at field-elongated plasma inhomogeneities including natural inhomogeneites as well as artificial inhomogeneities. The text also explains how inhomogeneities can create focusing effects and can capture and channel radio waves in the ionosphere-ground surface waveguides and transmit information over long distances.