  A thin-shell wormhole is theoretically constructible by surgically grafting
together two Schwarzschild spacetimes using the so-called cut-and-paste
technique. By describing such a wormhole as the limiting case of a spherical
shell, it is shown that the structure must be unstable to linearized radial
perturbations. Some earlier studies by the author et al. have shown, however,
that under certain conditions, thin-shell wormholes can be stable.
