This is a consistent treatment of the material-independent fundamental
equations of the theory of porous media, formulating constitutive
equations for frictional materials in the elastic and plastic range,
while tracing the historical development of the theory. Thus, for the
first time, a unique treatment of fluid-saturated porous solids is
presented, including an explanation of the corresponding theory by way
of its historical progression, and a thorough description of its current
state.