The Guardians is a fascinating account of the League of Nations’ ‘mandate system’, put in place to oversee administration of former German and Ottoman colonies between the wars. It provides a great insight into the early history of ‘development’ efforts and how colonial powers tried to justify and explain them to an international public. Perhaps even more important, the book reminds us how fragile ‘internationalism’ is once great powers lose interest in it – a tough lesson for our own times.