The Mastery Concept in the New World

I suffer from perioresis the only way I can get through all the long plane fights I have to take on a book tour is by reading either rock and roll biographies or military history. In the past four weeks I could pass an exam on Chuck Berry's history and inner life and on landing on Juno beach on D-Day. The problems that seemed overwhelming in peace time get solved in wartime remarkably quickly. A group of schools in America follow something called the mastery concept, based on mastering certain things for children rather than exams.