" ... he who repeats a thing in the name of him who said it brings deliverance to the world ... " Mishnah, Sayings of the Fathers 6; 6 Main Objectives The present book intends to fulfill a number of purposes, which are arranged under the following scheme: 1. A topical review of main subjects in fractography, that branch of science which analyses fracture surface morphology and related features and their causes and mechanisms in technological materials. Among the materials that bear significant affinities to rock are in­ organic glass, ceramics, metals and polymer glass. 2. A historical review of the main studies published to date on rock fractography. In both these fields of review, one is confronted by the similarities between small-scale (micro metre) and large-scale (tens of metres) fracture surface morphologies. The similarities, on the one hand, and the differences on the other must surely promote further development of fractographical approaches in structural geology, where extrapola­ tion from microfractography to large-scale fractography is virtually a directive. As geologists become more familiar with the fractography of rocks, they undoubtedly will become aware of the great power of this descriptive discipline as a tool, in both qualitative and quantitative analysis. Rock fractography must yet be routinely applied in the structural analysis of rock formations in which fracture morphology is sufficiently prominent or extensive.