Porous materials are heterogeneous media with unique microstructures, leading to interesting effective properties on which many different applications are based. In particular, porous ceramics combine the generic performance features resulting from the geometry and topology of the porous microstructures with the intrinsic properties of ceramics as a specific class of materials. In this book, Chapter One reconsiders and clarifies traditional classification schemes for porous ceramics that are based on processing, microstructure, properties, and to some degree also applications, and proposes partly new classification schemes, including a curvature-based classification of microstructures that may be useful alternatives to the more traditional schemes. Chapter Two presents a comprehensive review of microstructure peculiarities, mathematical models, methods of fabrication and measurements, as well as systematic experimental data for different types of porous ceramics and piezocomposites. Chapter Three introduces the superplastically fabricated ceramics mainly focused on the combination of 3 mol% yttria stabilised zirconia (3YSZ) and a silicon carbide (SiC) as a matrix and foam agent, respectively. Chapter Four reviews direct foaming techniques used for the preparation of cellular ceramics. Chapter Five presents a derivation of the generalised relationship between the ultrasonic attenuation and dispersion based on linear response theory. Chapter Six studies optical phenomena in porous percolating systems.