The book offers an in-depth look at ferromagnetic resonance, demonstrating its functions and concepts. It lays emphasis on current developments in the interaction of science and technology of nano-structures like nano-wires, photonic crystals, spinel type nano- particles etc. Electromagnetic resonance techniques now play a pivotal role in science and technology. The method of ferromagnetic resonance is most vastly used in sprintronics, electronics, space navigators, remote control equipment, radio engineering, electronic computers, maritime electrical engineering, instrument making and geophysical programs of prospecting.