The aim of this book is to provide an overview on exciting nanoporous materials with respect to their fundamentals, characterisation, applications and research trends. The book presents the fundamentals of microporous materials, including natural and synthetic materials. It provides insight into their structure, synthesis procedures, properties and possible applications. Furthermore, the fundamentals of silica-based mesoporous materials (structure, synthesis, properties, applications) are described together with those of organic/inorganic porous frameworks. Moreover, the main characteristics of macroporous materials are given, followed by those of amorphous and graphene materials. Also, useful theoretical and practical principles are reviewed to give more insight in the use of nanoporous materials. The most important characterisation techniques are also illustrated; these are used to gain a better understanding of their behaviour in relation to their possible use. At the end, possible future research trends and challenges are discussed.