In capital-intensive upstream oil and gas, the difference between success and underperformance is rarely determined by technical capability alone. More often, it is determined by when critical knowledge becomes available relative to when capital is committed. Sequencing Wells Under Uncertainty reframes one of the most overlooked variables in field development: the order in which wells are drilled. Traditionally treated as a matter of logistics and scheduling, well sequencing is shown here to be a strategic architecture of learning—one that directly shapes decision quality, capital efficiency, and long-term asset value. Drawing on more than seventeen years of upstream experience across appraisal and development environments, this book presents a structured framework for designing campaigns in which learning precedes commitment. It introduces practical tools such as hypothesis-driven sequencing, information-value mapping, knowledge-threshold gating, and the Learning-First Protocol—each designed to ensure that the uncertainties most critical to major investment decisions are resolved before those decisions become irreversible. Through clear conceptual models, realistic scenarios, and disciplined analysis of common failure patterns, the book demonstrates how misaligned sequencing leads to predictable outcomes: facility designs based on incomplete understanding, capital lock-in against incorrect reservoir models, and value erosion that becomes visible only after it is too late to correct. This is not a book about slowing down development. It is a book about sequencing intelligently—so that progress is built on knowledge rather than assumption. Written for senior upstream leaders, asset teams, and capital allocation decision-makers, this work provides a new lens through which to design appraisal programs, challenge development timelines, and protect value in high-uncertainty environments. Because in the upstream business, the question is not whether you will learn. It is whether you will learn in time.