The application of surface geochemical methods to finding petroleum is based on the detection of hydrocarbons in the soil that have leaked from a petroleum reservoir at depth. While the "seal" over the deposit was once considered impermeable, surface geochemistry data now show that such leakage is a common occurrence. Despite its simplicity and low costs, surface geochemistry remains controversial because, until now, there was no objective and in-depth treatment of the various methods of surface geochemistry for oil exploration. Written by a successful oil finder, this practical guide: surveys a broad array of surface geochemistry techniques, from soil gases to microbiology, and provides clear strategies for applying them to the high-stakes art of petroleum exploration; offers numerous case studies, both successes and failures, to show the strengths and weaknesses of different approaches; examines statistical and spatial variation, surveys, and models in surface geochemistry, demonstrating how each analytical tool can be used to optimize accuracy; integrates surface geochemistry data interpretation with data from conventional methods of oil exploration, and considers the economics of surface geochemical approaches; and discusses key topics that have been neglected in the literature, such as grid design and the effects of soils. Geologists, geophysicists, geological engineers, and exploration managers involved in petroleum exploration will gain valuable insights from this volume. By presenting and evaluating each method of surface geochemistry in a neutral tone, this volume enables the reader to select and employ these methods with greater confidence.