Layered double hydroxides are one of the variety of names given to a family of layered materials first discovered in Sweden in 1842. These materials are interesting because their layer cations can be changed among a wide selection, and the interlayer anion can also be (nearly) freely chosen. Like cationic clays, they can be pillared and can exchange interlayer species -- thus increasing applications and making new routes to derivatives. The principle areas of application include catalyst support, anion scavengers, polymer stabilisers, and antacids. In the last several years, reviews and studies of LDHs have dealt with these uses. This book aims to update the current body of LDH knowledge from a wide array of views. The first section addresses the synthesis and physiochemical characterisation of these materials, and section two focuses on the applications of LDHs.