  The problem of accounting for the quantum degrees of freedom in passing from
massive higher-spin potentials to massless ones and its inverse, the
"fattening" of massless tensor potentials of helicity $\pm h$ to their massive
$s = |h|$ counterparts, are solved - in a perfectly ghost-free approach - using
"string-localized fields". This approach allows to overcome the Weinberg-Witten
impediment against the existence of massless $|h| \geq 2$ energy-momentum
tensors, and to qualitatively and quantitatively resolve the van
Dam-Veltman-Zakharov discontinuity concerning, e.g., very light gravitons, in
the limit $m \to 0$.
