Structural geology is the branch of earth sciences that focuses on understanding the processes by which geological materials deform. Structural geologists use the rock record to study naturally deformed rocks, an endeavor that relies upon both fieldwork and, to an increasing degree, the use of microstructural observations to characterize deformed rocks. Other academic disciplines – such as branches of geophysics, engineering, materials science, and physics – share the goal of characterizing and understanding how natural materials deform. Those fields focus on laboratory deformation experiments or theoretical models of material behavior.

This began as an attempt to write the book that we wish we had read when we were trying to learn geostatistics, a task that turned out to be much more difficult than we originally envisaged. To the many people who provided encouragement, support, and advice throughout the writing of this book, we are very grateful.

We owe a lot to Andre Journel, without whom this book would never have been written. In addition to providing the support necessary for this project, he has been an insightful technical reviewer and an energetic cheerleader.

Why is economic geology essential to our progress? It has been said that agriculture is the most basic of man's activities, but in this time of overpopulation and indeed in the preceding centuries it would have been impossible to feed the world's teeming millions without recourse to mining and the use of minerals and metals for ploughing, fertilization, harvesting, food preparation and so on. Indeed, of these two basic industries— agriculture and mining—mining is the older. It started some 500000 years ago when man commenced exploring for tool-making materials — flint, obsidian, quartzite were chipped and ground to sharp cutting edges. Early man found that some localities were richer than others and began to search for these richer deposits, to mine them, establish axe factories and to trade in the finished products. He soon developed an appreciation of their geological occurrence. For example, by 3 000 B.C. large underground flint mines were in operation at Grime's Graves in Norfolk, U.K. and it is clear that the miners had noted that particular horizons in the chalk host rock carried the best and most numerous flints.

The onset and rapid spread of canals across the face of Britain in the late eighteenth century, closely followed by the building of the railway network in the early nineteenth century, were largely responsible for making the study of the strata, or stratigraphy, a subject of both practical and economic value. It is not surprising, therefore, that it was a land surveyor and canal engineer, William Smith (1769–1839), working initially in southern and eastern England, who first worked out that rock strata were not randomly disposed around the country but arranged in a definite order.