Book excerpt: This book deals with one of the most attractive fields in material science and technology research. In fact, the concept of organic–inorganic hybrid materials is applied to a wide variety of approaches that include materials with inorganic and/or organic nature with respect to their matrices and/or dispersed phase. The present book compiles one editorial and eleven approaches to the topic, and intends to provide a transversal idea about what the field of the so-called organic–inorganic hybrid materials means in actual scientific scenarios. In any case, the role is pointed out of the interphase between the components as the critical aspect to consider, as a way to enhance and understand these components in order to design materials with "tailor-made" organized structures considering the increasing nano-, meso-, micro- and macro-scales.