Wonderful story. Two boys – united by friendship and a determination to pass through school entirely unnoticed – discover a strange machine, hidden in a cave, and take it home. Given that the cave also contains the skeleton of a Roman centurion, the machine must be old. But did the Romans build machines?  Trying to figure out what it can do (pretty well everything turns out to be the answer in the end) causes them to blow their school anonymity as they start asking questions (shock, horror) and they even start to study independently. Norriss writes with a delightfully light touch and the two heroes, and the suspicious deputy headmistress, are wonderful creations.

And, on further thought, I’m going to give this book the ultimate 5-star accolade: it really is one of the best children’s books I’ve ever read.