The discovery and fabrication of new materials have opened the gate for new research fields in science and technology. The novel method of fabricating graphene, a purely 2D carbon lattice, and the discovery of the phenomenon of giant magnetoresistance (GMR) in magnetic multilayers are not exceptions. The latter has brought about the creation of the new technological field of spintronics, which utilizes both spin and charge degrees of freedom of electrons. As for the former, many applications have been proposed; however, no practical devices have yet been developed in the field of spintronics. The aim of this book is to provide possible hints to overcome the difficulties in graphene applications in the field of spintronics by comparing the physical properties of graphene and magnetoresistive (MR) phenomena in spintronics. The book will be useful for advanced undergraduate students and graduate students of physics, chemistry, and materials science and young researchers in nanotechnology and the field of spintronics.