“The Callendar family . . . is human and real, full of noise, squabbles and faults . . . it would be unfair to reveal the role the Callendar children play solving a frightening and realistic world crisis . . . John Verney is obviously writing far more for his own pleasure than for children and this is the way the best children’s books get written.”—Madeline L’Engle, New York Times
“[A] marvellous thriller for children.”—A. N. Wilson
"All the qualities of vitality and enjoyment, of laughter and life, of invention and poetry and love, of which we seem starved, are here in full measure."—The Times Literary Supplement
"The whole thing whips itself into a state of enormous excitement and complication, like a whodunnit, but much livelier than most."—The Guardian
"A chaotic romp centered around the Cold War which encompasses family politics, nuclear science, ponies, unscrupulous spies and sibling rivalry. It has a sharp-talking female protagonist, is very funny and highly entertaining."—Jojo Moyes, author of Me Before You