Book excerpt: This book presents a collection of chapters on modern bioelectrochemistry, showing different aspects of emerging techniques and materials, biodevice design and reactions. The chapters provide relevant bibliographic information for researchers and students interested in electrochemical impedance spectroscopy applied in biodevices, trends, and validation on impedimetric immunosensors in the application of routine analysis, electrochemical–surface plasmon bioanalytics and carbon nanomaterials in electrochemical biodevices, insights on inorganic complexes and metal based for biomarkers sensors, bioelectrodes and cascade reactions and field effect-based reactions.