This detailed study presents an accessible examination of how upstream petroleum activities are regulated in developed and developing petroleum countries. It includes a particular focus on the granting of access to petroleum resources, and incorporates a thorough consideration of the concept of Lex Petrolea. Different countries utilise a variety of legal models for regulating the exploitation of petroleum resources and two internationally recognised systems of managing natural resources are salient: concessionary systems and contractual systems. Expert contributors provide a detailed and insightful overview of the licensing and concession system that is used to award access to petroleum in many countries. They address topics such as auctions and work program bidding, and consider contexts such as offshore petroleum and the Russian system. The book considers the international nature of petroleum, alongside how licenses are granted under the bid and discretionary system. It includes a comparative analysis of the award of licenses in the countries discussed. This discerning and comprehensive work will be a useful entry point for students embarking on study in petroleum law. Academics will find this timely examination to be an indispensible overview of upstream operations. Practitioners will find this book an illustrative review of the origins of issues surrounding regulatory frameworks in managing natural resources.