Book excerpt: This book focuses on the basic electrochemical applications of DNA in various areas, from basic principles to the most recent discoveries. The book comprises theoretical and experimental analysis of various properties of nucleic acids, research methods, and some promising applications. The topics discussed in the book include electrochemical detection of DNA hybridization based on latex/gold nanoparticle and nanotubes; nanomaterial-based electrochemical DNA detection; electrochemical detection of microorganism-based DNA biosensors; gold nanoparticle-based electrochemical DNA biosensors; electrochemical detection of the aptamer-target interaction; nanoparticle-induced catalysis for DNA biosensing; basic terms regarding electrochemical DNA (nucleic acids) biosensors; screen-printed electrodes for electrochemical DNA detection; application of field-effect transistors to label free electrical DNA biosensor arrays; and electrochemical detection of nucleic acids using branched DNA amplifiers.