Since its founding in 1987, the political and ideological dimensions of the terror organisation Hamas have been well discussed by scholars. In contrast, this innovative study takes a new approach by exploring the entire scope of Hamas's intelligence activity against its state adversary, Israel. Using primary sources in Arabic, Hebrew and English, Netanel Flamer analyzes the development of Hamas's various methods for gathering information, its use of this information for operational needs and strategic analysis, and its counterintelligence activity against the Israeli intelligence apparatus. The Hamas Intelligence War against Israel explores how Hamas's activity has gradually become more sophisticated as its institutions have become more established and the nature of the conflict has changed. As the first full-length study to analyze the intelligence efforts of a violent non-state actor, this book sheds new light on the activities and operations of Hamas, and opens new avenues for intelligence research in the wider field.