The present volume offers a state-of-the-art report on the various recent sci­ entific developments in the Theory of Porous Media (TPM) comprehending the basic theoretical concepts in continuum mechanics on porous and mul­ tiphasic materials as well as the wide range of experimental and numerical applications. Following this, the volume does not only address the sophisti­ cated reader but also the interested beginner in the area of Porous Media by presenting a collection of articles. These articles written by experts in the field concern the fundamental approaches to multiphasic and porous materials as well as various applications to engineering problems. In many branches of engineering just as in applied natural sciences like bio- and chemomechanics, one often has to deal with continuum mechanical problems which cannot be uniquely classified within the well-known disci­ plines of either "solid mechanics" or "fluid mechanics". These problems, characterized by the fact that they require a unified treatment of volumetri­ cally coupled solid-fluid aggregates; basically fall into the categories of either mixtures or porous media. Following this, there is a broad variety of problems ranging in this category as for example the investigation of reacting fluid mix­ tures or solid-fluid suspensions as well as the investigation of the coupled solid deformation and pore-fluid flow behaviour of liquid- and gas-saturated porous solid skeleton materials like geomaterials (soil, rock, concrete, etc. ), polymeric and metallic foams or biomaterials (hard and soft tissues, etc).