When Michael Fordham was introduced to Dr Seuss's "Butter Battle Book" he immediately recognised its potential value in the classroom as a popular interpretation of the Cold War. Wanting his Year 9 pupils to explain how and why the past has been interpreted in different ways he shows the potential pitfalls inherent in asking pupils to explore how one period sees another, and how he addressed these challenges when planning his enquiry. In this article he demonstrates that if pupils are to explain why interpretations were produced they need to have secure knowledge of multiple periods, both of the period being interpreted and the period doing the interpreting.