Originally published as Polar babies by Random House Children's Books, 2000. Originally published in hardcover by Random House Children's Books in 2007 Originally published: New York : Random House Children's Books, 2019 Originally published in hardcover: New York : Random House Children's Books, 2010 Originally published : London : Meadowside Children's Books, 2004. Originally published in hardcover by Harcourt Children's Books, 1993 Originally published in hardcover: Harcourt Children's Books, 2005 Originally published in paperback by Random House Children's Books, New York, in 1974 Originally published: Great Britain : Orion Childrens Books, 2004. Originally published: London : Macmillan Childrens Books, 2004.