Slaves Of The Son Of Heaven is a survivor testimony. Whitecross's risking with his life kept a diary, in 1944 before proceeding to Japan all men were searched by Kempeitai the Japanese military police, and Whitecross didn't have any choice but to hide and leave his scraps of paper. When the war ended, Eric Hirsch, a man who helped to hide it, returned to the camp and dug up the diary. In Japan Whitecross and his friend Maurice Barkley were determined to write a book and kept notes of their observations and accounts of their friends. Those had to be destroyed as they were too much risk.
I would also highly recommend Surviving The Sword: Prisoners Of The Japanese 1942-45 by Brian MacArthur and Prisoners of the Japanese by Gavan Daws
I think that, this edition published in 2000 would have benefited from an added note telling how ex prisoners of the Japanese were treated by their Australian government.