This book combines a literature study and the results of a longitudinal case study from the oil and gas sector the Ivar Aasen project to explore the notion of learning in project-based organizations. First, readers are provided with a thorough examination of previous research on project learning, which is presented in structured and comprehensible format. The author explores the circular relationship between learning and performance in projects and identifies the means and attitudes required to support this circular relationship both within projects and between projects. The second part of the book has a narrower focus, namely on improving the institutionalized level of learning in project-based organizations. The empirical findings are drawn from the longitudinal case study and provide some useful insights into learning in a complex and demanding environment characterized by continuous changes, extreme time pressure, a multiplicity of stakeholders, tremendous financial impact, and market uncertainty. The study is peer-reviewed and presented as an academic text.