It is an excellent book.
To me, it is a book about Auschwitz/Oświęcim and how a German finds undeniable evidence of extermination.
It makes you think, "What would I have done in Germany, in 1938?" For the West, that question is the ghost in every man’s past. The answer to that question is the substance of your humanity.
After I read that book back in 1992 or so, it stimulated me to move from fiction to non-fiction, to educate myself about the holocaust. There is a lot to learn.
In the Soviet satellite states before 1989, they used to say that the Soviets had stolen their history, and that protecting and recovering what they could of that history was a vitally important task. It is good advice, not just for Poland, but for everyone in the West, including here in the USA.