Written by the leading experts in this field, this proceeding volume presents results from the International Symposium on “Functional Molecular Photoswitches For Energy Storage and Beyond” which took place in Barcelona, Spain on April 23th - 26th, 2024. This book is a comprehensive exploration of Molecular Switches and Devices (MOST) covering various aspects of those systems, including their performance criteria, computational discovery and evaluation, phase change behavior, catalysis, and functional applications such as energy storage devices and functional fabrics. It provides overviews of specific types of MOST systems, such as norbornadiene/quadricyclane, E/Z-azobenzene, and dihydroazulene/vinylheptafulvene and discusses their applications in devices and surface science. Additionally, it presents advanced topics like photoswitches in single-molecule electronics and molecular rotors and switches on surfaces. Overall, the book provides a thorough overview of the design, development, and applications of Molecular Switches and Devices in various fields of science and technology and is a great tool for researchers and graduates interested in this area of research.