  We describe a systematic method to construct arbitrary highest-weight
modules, including arbitrary finite-dimensional representations, for any finite
dimensional simple Lie algebra $\mathfrak{g}$. The Lie algebra generators are
represented as first order differential operators in $\frac{1}{2} \left(\dim
\mathfrak{g} - \text{rank} \, \mathfrak{g}\right) $ variables. All rising
generators ${\bf e}$ are universal in the sense that they do not depend on
representation, the weights enter (in a very simple way) only in the
expressions for the lowering operators ${\bf f}$. We present explicit formulas
of this kind for the simple root generators of all classical Lie algebras.
