This time, I'm simply going to quote from the book flap:
The story of The Boy in the Striped Pajamas is very difficult to describe. Usually we give some clue about the book on the jacket, but in this case we think that would spoil the reading of the book. We think it is important that you start to read without knowing what it is about.
If you do start to read this book, you will go on a journey with a nine-year-old boy called Bruno. (Though this isn't a book for nine-year-olds.) And sooner or later, you will arrive with Bruno at a fence.
Fences like these exist all over the world. We hope you never have to encounter such a fence.
The book is worthy of such an introduction. I nearly cried when I got to the end.
(If you're the sort that needs a bit more, I've stuck it in ROT-13 under the cut. Although I seriously advise going into the book without the information here. It is better if you discover what's going on right alongside Bruno.)
(The first paragraph is less spoilery than the second paragraph, although if you're smart, you can figure out what the second paragraph says from the first.)
Guvf obbx vf nobhg n Trezna obl va gur frpbaq jbeyq jne jubfr sngure orpbzrf gur pbzznaqre bs n cynpr ur bayl xabjf nf Bhg-Jvgu. Jung ur svaqf ba gur bgure fvqr bs gur srapr vf n obl.
Bs pbhefr, gur cynpr vf npghnyyl Nhfpujvgm, naq gur obl ba gur bgure fvqr bs gur srapr vf n Wrj. Gur fgbel tbrf sebz gurer.