This document provides a summary of the book "Flying Off Course IV" by Rigas Doganis. The book is 352 pages published in 2009 by Routledge. It provides an explanation for why the airline industry has experienced high growth but only marginal profits. The fourth edition of the book has been largely re-written and updated to account for recent sweeping changes in the airline industry. It includes new material on topics like airline costs, open skies, air cargo economics, and trends in airline pricing. The book also contains two new chapters on the economics of low-cost carriers and the future prospects of the industry.