Porosity influences physical and chemical properties of solids to a high degree. Porous materials have manifold application possibilities in diverse areas. Size, form, arrangement and accessibility of the pores are important characteristics, as well as magnitude and nature of the inner surface. Typical examples - solid foams, porous alumina, silica with ordered mesoporosity, Vycor (R) glass and aerogels - were selected as materials with different pore structures and for discussion of preparation strategies.