This book is great for parents of children who are teenagers (or who will be soon). The author gives interesting details about his experience of bringing up children bilingually in the USA (with visits to Francophone Canada). The discussion of how parents' influence wanes as the children go through adolescence is important. The book also very usefully documents and quantifies the impact of regular holidays to where a child's minority language is spoken. My one criticism of the book is that at times the author generalises from his experience with three children to speculate about all children - and I am not sure that this is always justified. Although heavier on evidence than some books, this book is readable - you just need to stick with it - and anyway there are a couple of chapters on methodology and the statistics that you can safely skip if you are just an interested parent.