In the previous chapter, we considered the importance of subject knowledge in teaching about sustainability and the environment. Looking afresh at the geography curriculum may have helped you to see how relevant many of the traditional topics of geography are to a curriculum for sustainability and the twenty-first century. There is so much that a primary teacher needs to do if children are to have the necessary background of knowledge and understanding to become informed citizens, capable of intelligent participation whenever environmental issues are debated. Yet a question remains. Mere ‘book learning’ has always been thought insufficient by the practically experienced. To echo the theme of an earlier chapter, subject knowledge is ‘necessary but not sufficient’.