  If the small and large coupling behavior of a physical system can be computed
perturbatively and expressed respectively as power series in a coupling
parameter $g$ and $1/g$, a Pad\'{e} approximant embracing the two series can
interpolate between these two limits and provide an accurate estimate of the
system's behavior in the generally intractable intermediate coupling regime.
The methodology and validity of this approach are illustrated by considering
several stationary state problems in quantum mechanics.
