  We list all metrics of arbitrary signature in four dimensions which admit
complete separation of variables in the Hamilton--Jacobi equation for geodesic
Hamiltonians. There are only ten classes of separable metrics admitting
commuting Killing vector fields, indecomposable quadratic conservation laws,
and coisotropic coordinates. Canonical separable metrics parameterized by
several (up to twelve) arbitrary functions of single coordinates are written
explicitly. The full set of independent conservation laws in involution for
each canonical metrics is also found.
