Resonance Effects of Excitons and Electrons : Basics and Applications This book presents the various types of resonance effects on excitons biexcitons and the local electronic centers (LEC) in solids such as paramagnetic and paraelectric resonances on excitons exciton acoustic resonance at intra and interband transitions radio optical double resonance on excitons hole nuclear double resonance on localized biexcitons ENDOR and acoustic ENDOR on LEC. The criteria for the generation of coherent photons phonons and magnons by excitons are explained. The interactions of excitons and biexcitons with paramagnetic centers and nuclear spins the indirect interaction between the PC through a field of excitons as well as the quasienergy spectrum of excitons and spin systems are discussed. It is proved that the interaction of paramagnetic centers with excitons increases the spin relaxation rate of paramagnetic centers in comparison with the case of their interaction with free carriers. The giant magneto optical effects in semi magnetic semiconductors are theoretically interpreted. In recent years a new perspective has been added to these systems and their interactions: they can be used for storing and processing information in the form of quantum bits (qubits) the building blocks of quantum computers. The basics of this emerging technology are explained and examples of demonstration type quantum computers based on localized spins in solids are discussed