Book excerpt: This book delivers a comprehensive overview of the characteristics of several types of materials that are widely used in the current era of supercapacitors; namely, architectured carbon materials, transition metal oxides and conducting polymers. It provides readers with a complete introduction to the fundamentals of supercapacitors, including the development of new electrolytes and electrodes, while highlighting the advantages, challenges, applications and future of these materials. This book is part of the Handbook of Nanocomposite Supercapacitor Materials. Supercapacitors have emerged as promising devices for electrochemical energy storage, playing an important role in energy harvesting for meeting the current demands of increasing global energy consumption. The handbook covers the materials science and engineering of nanocomposite supercapacitors, ranging from their general characteristics and performance to materials selection, design and construction. Covering both fundamentals and recent developments, this handbook serves a readership encompassing students, professionals and researchers throughout academia and industry, particularly in the fields of materials chemistry, electrochemistry, and energy storage and conversion. It is ideal as a reference work and primary resource for any introductory senior-level undergraduate or beginning graduate course covering supercapacitors.