[en] The relationship of phonon anomalies and lattice instabilities to high Tsub(c) superconductivity is explored. Inelastic neutron scattering studies have revealed an intimate and dramatic relation between certain phonons and lattice transformations, real or incipient, for moderate to high Tsub(c) superconductors, which are minimal or nonexistent in very low Tsub(c) or nonsuperconductors. Experimental evidence is presented for a wide variety of superconducting materials and possible theoretical explanations for their behaviour are discussed