This book introduces the main aspects of modern applied electrochemistry. Starting with the basics of thermodynamic background, structure of interfaces and selected techniques used in analytical and material chemistry, the authors address the principles of electrochemistry in material science: corrosion, electrocatalysis, electrodeposition, energy storage and conversion. The application of nanostructured materials in these processes, as well as interfacing of electrochemistry with biology and medicine is discussed. The final part of the book is devoted to photoelectrochemistry and solar energy conversion in photoelectrochemical cells of various types. The goal of this book is to show that electrochemistry has many applications, not only for understanding of various phenomena in nowadays life but also in practical devices and can stimulate new science-enabled technologies, nourishing leaps from bench-top to large-scale industries, providing also means for protecting our environment.