The emphasis on the power of secure substantive knowledge reflected in recent curriculum reforms has prompted considerable interest in strategies to help students retain and deploy such knowledge effectively. One strategy that has been strongly endorsed by some cognitive psychologists is regular testing; an idea that Nick Dennis set out to test for himself. While he found, as others have done, that students' performance in low-stakes tests and their use of substantive knowledge in explanatory essays certainly improved as they undertook regular "quizzes", he also discovered that securing knowledge in one format does not "necessarily" ensure that it will be used effectively in another. His conversations with the students involved also alerted him to the need to consider both the ways in which tests of this kind are perceived by the students and how he could actively support his students in developing and storing knowledge in ways that made it both accessible and meaningful to them. By looking back to periods in which scholars were much more reliant on effective recall, Dennis reminds teachers both of the power of the visual and of the need to think very deliberately about creating coherent structures in which new knowledge can be effectively located.