9. Tomorrow, when the War Began by John Marsden

I've taught this book a few times and absolutely love it. I even got my other half hooked on the series when we were dating in the U.S., buying the set from Amazon. It's a great book as a self-contained volume too. The progression in character development is gradual but real - the change from kids to young adults with awareness and a growing sense of ruthlessness is very believable. I think the series drags around the fifth book but this first volume is pacy and well crafted.