This book presents a comprehensive theoretical study of the electromagnetic eigenwaves propagating perpendicular to the axis of symmetry in various cylindrical waveguide-structures filled with magneto-active plasma. It is the second, updated and significantly expanded edition of our book “Surface Flute Waves in Plasmas. Theory and Applications”, published in 2014 in the “Springer Series on Atomic, Optical, and Plasma Physics”. First, the text is complemented by a study of the wave energy rotation around the axis of the waveguides. Second, excitation of these waves by an electron beam...