Metamaterials and metasurfaces are developing exciting new frontier researches on reconfigurable materials with promising applications on tunable and active devices. The combination of metamaterials and microsystems not only uncap the controllability limits of optical metamaterials, but also pave the way for vast applications. This book focuses on structural reconfiguration of metasurfaces and metamaterials using microsystems, which have previously been developed for tiny machines and droplets formations. It covers multi-disciplinary researches on reconfigurable metamaterials and metasurfaces revealing their potential applications on densely integrated devices with working frequencies ranging from GHz to infrared region. Topics like MEMS metamaterials, frequency selective surface, photonic reconfigurable metasurfaces, and microfluidic metamaterials are just a few examples, which present lively research communities within the scope of this book. This book is intended for undergraduate and graduate students who are interested in fundamental science and technology of micro-optics and artificial materials, researchers in the field of reconfigurable and tunable metamaterials, and engineers working on tunable lens, Lidar, beam steering devices, or other applications.