Year by year the Earth sciences grow more diverse, with an inevitable increase in the degree to which rampant specialization isolates the practitioners of an ever larger number of sub fields. An increasing emphasis on sophisticated mathematics, physics and chemistry as well as the use of advanced technology have. set up barriers often impenetrable to the uninitiated. Ironically, the potential value of many specialities for other, often non-contiguous once has also increased. What is at the present time quiet, unseen work in a remote corner of our discipline, may tomorrow enhance, even revitalize some entirely different area. The rising flood of research reports has drastically cut the time we have available for free reading. The enormous proliferation of journals expressly aimed at small, select audiences has raised the threshold of access to a large part of the literature so much that many of us are unable to cross it. This, most would agree, is not only unfortunate but downright dangerous, limiting by sheer bulk of paper or difficulty of comprehension, the flow of information across the Earth sciences because, after all it is just one earth that we all study, and cross fertilization is the key to progress. If one knows where to obtain much needed data or inspiration, no effort is too great. It is when we remain unaware of its existence (perhaps even in the office next door) that stagnation soon sets in.

Deformation of the Earth’s crust happens at a multitude of scales, ranging from submicroscopic to planetary. Tectonics explores structures and processes from regional to global, differentiating itself from the material covered in most structural geology textbooks. Moores and Twiss emphasize basic principles and methodologies of tectonics, embracing the time-honored perspective of using present processes to understand the past. Comprehensive in scope and detail, coverage includes the effects of plate motions and reconstructions and the resultant structures associated with active rift, transform, and subduction boundaries as well as triple junctions and collision zones; deformations of both the ocean basins and the continents; and orogenic belts. Moores and Twiss present tectonics as an open-ended field of study in which assumptions can be challenged and interpretations changed. The authors emphasize the use of models as a means of understanding observations and putting them in context to maintain a distinction between what we know from observing the Earth and what we infer from interpretation.

Demonstrating the multidisciplinary approach currently used to understand Jurassic magmatism and tectonics in western North America, 19 papers report a wealth of new data in the fields of structural geology, igneous petrology and isotope geochemistry, geochronology, sedimentology, and volcanology. T