Spin Exchange and Electron Transfer -- Spin Exchange Processes Involving Excited Triplet States -- Spin Electron Dipolar and Contact Interactions -- Spin-Selective Processes of Electron and Nuclear Spins -- Experimental Methods of Investigation of Electron Spin Interactions Based on ESR Phenomena - Continuous Wave EPR Measurements -- Experimental Methods of Investigation of Electron Spin Interactions Based on ESR Phenomena: Pulse ESR Measurements -- Miscellaneous Methods of Investigation of Electron Spin Interactions Based on Optical and Other Techniques -- Electron Spin Effects in Chosen Chemical and Physical Processes -- Magnetic and Electromagnetic Fields Effects on Chemical and Biological Processes -- Electron Spin Interactions in Investigation of Structure and Spin State of Organic and Metallo organic Compounds -- Electron Transfer in Biological Systems. Light Energy Conversion -- Spin Labeling Methods. .