‘Course not,’ Ashes said, jumping onto the table and sending up a little billow of dust. ‘He’s a servant, like the rest of us. Go on, ask him what he really is.’

Mr Wurms glared at the cat. Alice swallowed.

‘That doesn’t seem like a very polite question,’ she ventured.

‘A very astute judgement,’ Mr Wurms said. ‘I’m glad you have more sense than this . . . rat-catcher.’

‘Rat-catcher! Rat-catcher?!’

‘So,’ Alice said, over the sounds of Ashes’ indignation, ‘I’m eager to get started. What am I to be doing?’

‘Looking for magic,’ Mr Wurms said. His licked his lips, his tongue disturbingly pink and agile. ‘Has Master Geryon explained it to you?’

‘He hasn’t explained anything,’ Alice said.

Mr Wurms blinked behind his enormous spectacles and gestured vaguely at the bookshelves all around him. ‘What do you see here?’

‘Books?’

‘Indeed, books. They are the ocean in which magic swims.’

‘These are magical books?’

‘Not in themselves, no. But every so often, somewhere among them, a particular word or phrase or sentence achieves a meaning that goes beyond the natural. If I were to look at it, I would see only dry letters on paper, but to you they would express a flicker of power.’

‘But if you can’t see magic, then how can it be your job to find it?’

‘One thing at a time. Now, those fragments must be extracted as a surgeon might extract a foreign body from a patient. Then they can be combined to serve as the raw material for magic. Master Geryon can weave them together, one to the next, and create new books of the sort you mentioned.’

‘Prison-books?’

‘And portal-books, and world-books, and books that lead to the bottom of the ocean, and a hundred other things. What he does with his books and why he does it is not for us to know. Our task is to comb the library for the fragments so that he might do it.’

Alice frowned. ‘Haven’t you looked through all these books already? They have to have been here for ages.’

‘Magic is not something stamped into a book by a printing press, girl! Where it takes root and how long it lasts, no one can say. Have you never picked up a book you’ve read before, and found it speaks to you in a new way?’

Alice nodded.

Mr Wurms shrugged. ‘Books age, they yellow, the pages dry and crackle and tear. Who can tell what tiny defect will change simple paper and ink into true meaning? Certain authors, certain printers, even certain binders or typesetters are more likely to generate magic than others. We suspect that those who have a bit of the Reader’s talent leave little traces of their passage wherever they go, like a man with paint on his shoes. Master Geryon’s collection is among the finest. But even here, we must dig carefully to find the scraps of value.’