Synopsis Structural geology is obviously one of the more important subjects for geoscientists working in petroleum industry. Folds and faults in deformed rocks make traps for hydrocarbon accumulation. Also, large-scale deformations, the so-called tectonics, control the architecture of petroliferous sedimentary basins. It is the primary job of a structural geologist to interpret geological map and field data, and infer geometry of large scale folds and faults. However, geoscientists with varied specializations and working with different kinds of data may also be called upon to make structural interpretations. It is imperative that geoscientists with different specializations working in oil industries have basic working knowledge on structural geology. In this publication, the focus is on topics that I think should be of common interest to most petroleum geologists and geophysicists. This book will be particularly useful to those who did not have a thorough grounding in structural geology. Also, students in a bachelor level structural geology course may find this book useful.