This book is written and edited by experts and academics already active in the oil and gas industry, and addresses students and practitioners alike. It aims to familiarize them with salient features of oil and gas service contracts. The book provides a concise description and, to a lesser extent, analysis of the main features of service contracts of the types commonly used in the oil and gas industry. Writers and editors come from different legal traditions and practice in different jurisdictions, including UK, Iran, Brazil and Mexico. Service contracts are as broad as their name suggests, comprising a wide array of contracts. However, a clear distinction exists between contracts where one party to the contract is a sovereign state or neither is. This has been the basis for organizing the present book in two parts.