  We propose a simple Ginzburg-Landau free energy to describe the magnetic
phase transition in solid $^3$He. The free energy is analyzed with due
consideration of the hard first order transitions at low magnetic fields. The
resulting phase diagram contains all of the important features of the
experimentally observed ph ase diagram. The free energy also yields a critical
field at which the transition from the disordered state to the high field state
changes from a first order to a second order one.
