  A 1-matrix model is proposed, which nicely interpolates between
double-scaling continuum limits of all multimatrix models. The interpolating
partition function is always a KP $\tau $-function and always obeys ${\cal
L}_{-1}$-constraint and string equation. Therefore this model can be considered
as a natural unification of all models of 2d-gravity (string models) with
$c\leq 1.$
