  We compare the theoretical anisotropic upper critical field $H_{C}(\Theta,T)$
of a quasi-two-dimensional d-wave superconductor with recent $H_{c2}$ data for
the layered organic superconductor $\kappa-(BEDT-TTF)_2Cu(NCS)_2$. We find
agreement both with regard to the angular and the temperature dependence of
$H_{C}$. This supports the suggestion that the Fulde-Ferrell-Larkin-Ovchinnikov
state (FFLO state) exists in this material for exactly plane-parallel
orientation of the magnetic field. Indications of precursor states, occurring
for small deviations from the plane-parallel field direction, are also pointed
out and further measurements for confirming the existence of the FFLO state are
proposed.
