In this new edition of the ASE Guide to Primary Science Education, two important areas are highlighted. The first is the importance of taking a scientific approach to teaching. This means using evidence, where it exists, in making decisions that affect teaching, and being sceptical about claims where there is no evidence. The complexity of the processes of learning and teaching means that finding convincing evidence in relation to teaching practices is more difficult than conducting a scientific experiment in a laboratory. What works in some classrooms may not be so effective in others. But it is always useful to try out what others find helpful - and there are many good ideas in this Guide - whilst collecting evidence of changes in children's engagement in learning. The second message continues the longstanding debate around the dual goals of science education: the development of conceptual understanding and the development of inquiry skills. We value learning with understanding, as opposed to rote learning, and have long recognised that this depends on children starting from their existing ideas and on teachers enabling them to develop 'bigger' ideas. However, this will only help children's scientific understanding if they are working Scientifically, that is, gathering and using evidence and developing the skills of inquiry. This takes time, not just for carrying out these processes, but also for reflecting on how this has been done and how it has led to ideas being changed. These messages form the backbone of this flagship ASE book, designed to assist beginning teachers and senior subject leaders alike.