An extensive study of GeV light-ion-induced multifragmentation and its possible interpretation in terms of a nuclear liquid–gas phase transition has been performed with the Indiana Silicon Sphere (ISiS) 4 π detector array. Measurements were performed with 5–15 GeV/ c p , p ¯ , and π - beams incident on 197Au and 2–5 GeV 3He incident on natAg and 197Au targets. Both the reaction dynamics and the subsequent decay of the heavy residues have been explored. The data provide evidence for a dramatic change in the reaction observables near an excitation energy of E * / A = 4 – 5 MeV / residue nucleon . In this region, fragment multiplicities and energy spectra indicate emission from an expanded/dilute source on a very short time scale (20–50 fm/ c). These properties, along with caloric curve and scaling-law behavior, yield a pattern that is consistent with a nuclear liquid–gas phase transition.