  We consider the Schwarz-Sen spectrum of elementary electrically charged
massive $N_R=1/2$ states of the four-dimensional heterotic string and show the
maximum spin $1$ supermultiplets to correspond to extreme black hole solutions.
The $N_L=1$ states and $N_L>1$ states (with vanishing left-moving internal
momentum) admit a single scalar-Maxwell description with parameters $a=\sqrt 3$
or $a=1$, respectively. The corresponding solitonic magnetically charged
spectrum conjectured by Schwarz and Sen on the basis of $S$-duality is also
described by extreme black holes.
