Book excerpt: This book presents a collection of chapters on modern bioelectrochemistry, showing different aspects of electron transfer reactions in biological systems and techniques. The chapters cover computer simulation, biomolecules on surfaces, direct and mediated electron transfer, electron transfer kinetics, surface-confined biomolecules, field-effect transistor effects, supramolecular electrochemistry, in situ and operando techniques in bioelectrochemistry. They provide relevant bibliographic information for researchers and students interested in computer simulation involving biomolecules on surfaces, processes of direct and mediated electron transfer kinetics of cytochrome c, surface-confined biomolecules for application in bioelectronics, sensitive devices based on field-effect transistors, insights on supramolecular electrochemistry with recent trends and perspectives and technological innovation on instrumentation applied in operando techniques field.