elonging is that sense of being somewhere you can be confident that you will fit in, a feeling of being safe in your identity and at home in a place. The ‘place’ at the heart of this book is school: one of the few shared social institutions that can create a sense of safety and belonging for young people or a sense of exclusion. Yet across many countries and con-texts, young people’s sense of belonging in school is declining. The book covers the two sides of the ‘belonging’ story. The first is the dis-piriting one which is reflected in the unacceptable state of affairs which characterise many school systems: rising levels of unhappiness; growing rates of exclusion from school; ongoing increases in mental health and wellbeing issues for many young people. The other side of the story is a profoundly optimistic one and is based on compelling evidence about the strong relationship between young people’s sense of belonging in school and their happiness, confidence and academic performance. As the book evolved, and the weight of this evidence grew, so did my optimism.