This book provides a concise summary about fundamental aspects of petroleum geology and geochemistry for graduate students, primarily from non-English-speaking countries. These fundamentals constitute about 40% of the book, while the remaining 60% deals with regional examples from petroleum geology of the Zagros basin of Iran. The regional examples are prepared using both published and unpublished (proprietary) data. The aim is to familiarize readers with the fundamental aspects of petroleum geochemistry and then provide typical examples from one of the world’s most prolific petroleum provinces.