Ah yes, the magical land of "the back". Endless capacity. It is for sure where we keep everything. The ~6 m2 office where we shelf extra copies of popular stuff we can't fit on the display. No lady, I ASSURE you, the book we sold out of four years ago that you are looking for is NOT in the back? If the system says zero copies, there are zero copies. The only times the system can be wrong is if a book was stolen, but we can only get false POSITIVES. No false negatives. Please leave.