A phase space approach to gravitational entropy

We examine the definition S = In Omega as a candidate function for "gravita tional entropy." We calculate its behavior for gravitational and density pe rturbations in closed, open and hat cosmological models and find that in al l cases it increases monotonically. We are also able to calculate the entro py density of gravitational radiation produced by inflation. We compare the results with the behavior of the Weyl-tensor squared. Applying the formali sm to black holes has proved more problematical.