Parameters that characterize interface fracture are defined, and procedures to measure them are discussed. The interface strength an is measured by using a novel laser spallation experiment, which uses a laser-induced stress wave to separate the interface. The intrinsic (G(o)) and total (Gc) fracture energies are measured using a double cantilever beam experiment performed at ambient and cryogenic temperatures, respectively. These experiments are used to obtain relationships between Gc and Go, and between sigma(o) and G(o), for interfaces between sputter-deposited polycrystalline Ta coatings and sapphire substrates. The intrinsic toughness and strength were modified by changing the orientation of the sapphire surface (basal and prismatic), while G(c) was varied by changing the test temperature (ambient and cryogenic) and the thickness (1-3 mu m) of the ductile Ta layer. Besides providing values that have interest in their own right, the work presented here provides a general framework for designing interfaces in bonded structures and serves as a basis to develop atomistic and continuum interface fracture models.