  We construct a class of composite fermion states for bilayer electron systems
in a strong transverse magnetic field, and determine quantitatively the phase
diagram as a function of the layer separation, layer thickness, and electron
density. We find, in general, that there are several transitions, and that the
incompressible phases are separated by compressible ones. The paired states of
composite fermions, described by Pfaffian wave functions, are also considered.
