I recall first reading this as a teenager, and it was a transformative part of growing up. Since then I have heard from many people that reading this memoir was an experience itself, and the definitive exposure to the Holocaust for them. Certainly the reviews on Amazon reflect that.
The greatness of this thin book is its haunting humanity, even in its plain unembroidered atrocity and quick descent into brutishness. There is no vivid redemption, no real heroes, just survival. When people say "Never forget," they mean the WWII Holocaust -- but this book reminds me that it also means "Never forget what lies under a thin veneer in every man and woman." The humanity is what we make of that veneer, how we maintain and strengthen it.