  We analyze the critical behaviour of the three-dimensional, three-state Potts
model in the presence of an external ordering field. From a finite size scaling
analysis on lattices of size up to 70**3 we determine the critical endpoint of
the line of first order phase transitions as (b_c, h_c) =(0.54938(2),
0.000775(10)). We determine the relevant temperature like and symmetry breaking
directions at this second order critical point and explicitly verify that it is
in the universality class of the three-dimensional Ising model.
