All [Garfield's] books deal in some way with an atmosphere of concentrated evil shot through with possibilities for good. Perhaps his wartime experiences have had something to do with the springs of his writing inspirations. On the other hand, the press handouts all tell us that he "has a passion for secrets and mystery". However they are sparked off, Leon Garfield's books are unique in children's literature.

He is as aware as any other author for children of the need for frequent action. Never a page is turned but something happens, and yet the overwhelming contribution of his books is that they deal in that old-fashioned quality, morality. At the centre of each story is a young person, a boy usually, whose life is impinged upon by mysterious forces for good and evil, their rightness or wrongness obscured by different shows and pretences or seemingly accidental occurrences. Is...