The Gravity Escapement (TWS)

You look around for clues. No sign of a break-in, though you suppose since the door was locked any potential thieves would have had time to clean up after themselves. The librarian remains conspicuously absent.

You have another glance around this little room. Neatly stacked on shelves, in box files, dusty tomes are labeled and organised in a system so esoteric you barely recognise it as such. In fact, one such may not exist at all. It bears the hallmarks of a few generations of librarians: some box files are organised alphabetically, but then abruptly jump into a decimalised subject-based system, which then moves into an aesthetically pleasing but organisationally disastrous system based on book heights. Interestingly enough, most of the history books discussing events outside or possibly critical of the Empire's dominion are piled in one corner, lying there in a seditious heap. Their box files seem to have been abandoned in favour of one ageing wooden crate. Upon the topmost volume rests a worn, sweaty bottom-print, and a dried-up apple.

They also have a fantastic collection of adventure novels. "Adventures". You know the sort.

Blushing furiously, you close the door behind you and replace the key to the Rare Books room. As you bend down to close the drawer, you notice an odd smear near the bottom of the late fees ledger. It almost looks as if someone has tried to smudge this fairly recent entry out. You can't tell what book this is, but it's clear the borrower was Daniel McCloud himself.

You close the drawer with the keys in it, and it shuts with a very final 'click'. You suddenly realise that this drawer must usually be locked.