The first steps in the study of geological structures are largely geometrical. This is true in the historical development of our knowledge of such structures, in the initial stages of any field investigation, and in the education of a structural geologist. This concern for geometry includes the methods of describing and illustrating the form and orientation of geological structures, and the solution of various dimensional aspects of these structures.

This book attempts to fill a need for an introduction to the geometrical techniques used in structural geology. I have sought an approach which is basic yet modern. The topics covered include well-established techniques, newer approaches which hold promise and an introduction to certain fundamental mechanical concepts and methods. Students who go no further in structural geology should have a working knowledge of the basic geometrical techniques and at least some appreciation of where the field is headed. Those who do go on, either in advanced courses or on their own should have the necessary foundation.

The first few chapters apply the methods of orthographic projection to the solution of simple structural problems. An introduction or review of these methods is given in Appendix A. Application to geological and topographical maps are included and extensive use is made of Mackin's powerful method of visualization – the down-structure view of geological maps.

The method of stereographic projection and the stereonet, together with the methods of plotting and solving angular problems are introduced fairly early.