Petroleum reserves are critical to the oil and gas industry, representing the recoverable amount of oil, gas, and natural gas liquids over time. Reserve forecasts are used by companies for planning, budgeting, and capital allocation, while energy lenders, investors, and government agencies rely on reserve estimates to make significant financial and policy decisions. However, the process of estimating and reporting reserves is often misunderstood outside the reservoir engineering profession, leading to misinformed decisions and financial risks. This book addresses the gap in non-technical resources on oil & gas reserves and reserve reporting, providing readers with an easily understandable yet thorough examination of the key concepts and principles behind reserve estimation and reporting. It aims to demystify the complexities of oil & gas reserves and guide decision-makers through the fundamentals of reserve evaluation and reporting. It is designed to become the go-to reference for energy and finance professionals across the globe, offering critical insights into oil & gas reserves and reserve reporting. It aims to be a valuable resource found on the desks of professionals who rely on reserves and reserve reports for making key decisions related to forecasts, investments, capital allocation, and valuation.