Publisher Summary This chapter provides an overview of homogeneous fluidization. The unrecoverable pressure loss in a fluid flowing through a bed of particles can be applied to beds expanded by various mechanical means to void fractions normally encountered only in fluidized systems. This chapter makes use of these relations in an analysis of the equilibrium state of homogeneous fluidization. The expansion characteristics of homogeneously fluidized beds are the subject of far more empirical study than theoretical analysis. This could be due to the uncomplicated nature of the experimental procedure, which involves simply the measurement of steady-state bed height as a function of volumetric fluid flux. The results are usually presented as the relation of volumetric fluid flux with void fraction which, unlike steady-state bed height is independent of the quantity of particles present. The constant particle volume relation enables void fraction to be calculated from steady-state bed height from the initial values of these variables in the packed bed. The chapter also discusses the primary forces acting on a fluidized particle.