The book is centered on how major curriculum reform shapes mathematics and the professional practices of teachers. This book documents in real time the implementation of a major government numeracy programme and its receipt by trainee and new teachers. It documents the complete life span of that initiative. The account is targeted at an international readership in terms of how curriculum reform more generally shapes mathematics in schools and the practices of teachers. A key dimension of the book is an alternative view of mathematics education research in which the task of teacher development is understood at policy level where large numbers of teachers were interviewed to assess how policies were being processed through individuals. The book provides an easy and accessible commentary utilising contemporary theory to describe how such teachers reconcile their personal aspirations with the external demands they encounter in negotiating their identities as professional teachers.