The Shape of War stems from the need to bring together in one volume the diverse experiences of modern Western counterinsurgency thinking, which later developed into the more articulate counterinsurgency doctrine, also known as COIN. Although warfare generally does not admit pre-established patterns, since everything in it is subject to sudden change, it is possible within this jagged subject matter to identify specific lessons related to armed rebellion. Historical analysis is a tool for understanding insurgencies' continuity and very nature, depending on where and when they occurred. The theme of The Shape of War concerns the Western doctrine of counterinsurgency and its development over the centuries, from the late 17th century to the present. Case studies support each historical period covered. The Shape of War was born out of the need to collect all the essential testimonies in one book to make it easier to consult the reading materials and, above all, to understand such a complex topic. Failure to appreciate some basic principles of irregular warfare has produced the poor results in geopolitics that are there for all to see. Afghanistan is only the most emblematic example of a myriad of failures attributable to superficial interpretations of the insurgency phenomenon. The value of The Shape of War lies precisely in its originality, in that never before has anyone treated the subject so comprehensively, using a comparative methodology that will help the reader so much as they move through the centuries and different chessboards. AUTHOR: Dr. Federica Saini Fasanotti is a nonresident Fellow in the Center for 21st Century Security and Intelligence, of the Foreign Policy program at The Brookings Institution. She is also a Senior Associate of ISPI in Milan. She is a historian specialized in counterinsurgency and asymmetric wars. Her fieldwork and research have covered, among others, Afghanistan, Libya, and the Horn of Africa. She has been a consultant on Libya for James Mattis, former US Secretary of Defense and for Terna Group, the first grid operator for electricity transmission in Europe. In September 2016 she testified before the U.S. House of Representatives Committee on Foreign Affairs about terrorism in Libya.