Ivan Southall was an award-winning Australian writer of young-adult fiction and non-fiction. He was the first and still the only Australian to win the Carnegie Medal for children's literature. His books include Hills End, Ash Road, Josh, and Let the Balloon Go. Also notable is Fly West, a book of true stories based on his experiences flying in Short Sunderland flying boats during the Second World War.
I must have read this book half a dozen times as a kid, and the rating reflects the joy elicited at that age. It is amusing to think of Southall's depiction of Martians as actually being considered somewhat plausible in a pre-Mariner mission world.