'What were the smaller ones?'

'I forget,' replied Havisham, tying the waistcoats into a bundle. 'Here, you're going to need this. Study it well if you want to pass your exams.'

She handed me my TravelBook, the one that Goliath had taken; within its pages were almost all the tips and equipment I needed for travel within the BookWorld.

'How did you manage that?'

Miss Havisham didn't answer. She snorted and pulled me towards the elevator again. It was clear that the twenty-second sub-basement wasn't a place she liked to be. I couldn't say I blamed her.

Miss Havisham relaxed visibly as we rose from the sub-basements and into the more ordered nature of the Library itself.

'Why do grammasites wear stripy socks?' I asked, looking at the bundle of garments on the floor.

'Probably because spotted ones are out of fashion,' she replied with a shrug, reloading her pistol. 'What's in the bag?'

'Oh, some – er – shopping of Snell's.'

Miss Havisham was a bit like a strict parent, your worst teacher and a newly appointed South American dictator all rolled into one. Which wasn't to say I didn't like her or respect her – it was just that I felt I was still nine whenever she spoke to me.

'So why did we sing "Jerusalem" to get rid of them?'

'As I said, those grammasites were Verbisoids,' she replied without looking up, 'and a Verbisoid, in common with many language students, hates and fears irregular verbs — they much prefer consuming regularverbs with the "ed" word endings. Strong irregulars such as "to sing" with their internal vowel changes – we will sing, we sang, we have sung — tend to scramble their tiny minds.'

'Any irregular verb frightens them off?' I asked with interest.

'Pretty much; but some irregulars are more easy to demonstrate than others – we could cut, I suppose, or even be, but then the proceedings change into something akin to a desperate game of charades – far easier to just sing and have done 'with it.'

'What about if we were to go? I ventured, thinking practically for once. 'There can't be anything more irregular than go, went, gone, can there?'

'Because,' replied Miss Havisham, her patience eroding by the second, 'they might misconstrue it as walked — note the "ed" ending?'

'Not if we ran," I added, not wanting to let this go, 'that's irregular, too.'

Miss Havisham stared at me icily.

'Of course we could. But ran might be seen in the eyes of a hungry Verbisoid to be either trotted, galloped, raced, rushed, hurried, hastened, sprinted or even departed.'

'Ah,' I said, realising that catching Miss Havisham out was about as likely as nailing Banquo's ghost to a coffee table, 'yes, it might, mightn't it?'

'Look,' said Miss Havisham, softening slightly, 'if running away killed grammasites there wouldn't be a single one left. Stick to "Jerusalem" and you won't go far wrong – just don't try it with adjectivores or the parataxis; they'd probably join in – and then eat you.'