‘It is possible that he never existed. And that the herder never owned the map,’ Goodwill said.

‘A cover story to hide its real origin,’ Ysbel said.

‘After failing to trace the chain of the map’s ownership,’ Swift said, ‘I tried to find out how Pilgrim’s tribe came to possess it. I had only a little hope of discovering anything useful. Forty years ago, when he’d first found the map, Pilgrim had asked me to search the Library of All People for others like it, and for images that might depict ogres meeting bears in the long ago. I looked in every corner and cranny of the public stacks and made enquiries amongst my peers in the trade, but failed to turn up anything of use to my old friend.’

‘But he has found something more recently,’ Goodwill said.

The two natives were sharing a look. Some kind of cosy complicity or mutual recognition. Like them, Ysbel was sitting crosslegged on a cushion, but her head was only a handspan from the ceiling and she felt clumsy and oversized in the small, spare space, uncomfortably aware that she was the stranger here amongst these strange people in this strange city on this strange Earth. An alien, a fugitive, a guest.

She said, ‘This is the thing you think will be of interest to me.’

‘You may have noticed the book on display,’ Swift said.

‘Is the map mentioned in it?’

‘The Library of All People was founded on the principle that knowledge should be shared freely, but the librarians soon decided that were some things that should not be shared and created a new set of stacks which the ordinary public could not access. The closed or forbidden stacks. Some of the items are documents which were sensitive or secret at the time of deposition, and can be released only after some specified period of time has elapsed. Others are heretical, sacrilegious or profane, or contain ideas believed to be dangerous. The recipe for gunpowder was famously one of the latter, banned and forgotten until it was rediscovered a century later.

‘I found the book you see on the lectern in the inventory of one of my fellow dealers, several years ago. It is almost as old as the Library itself, and lists documents and objects that were deposited in the closed stacks in the first twenty-two years after their creation. One of those items is something you may be interested in, because it is related to the mystery of the map.’

‘The possibility that your people met with bears long before they met with us,’ Goodwill said.

‘Why didn’t you find this item when you were trying to help Goodwill’s uncle?’ Ysbel said to Swift.

‘I was young and new to my trade, and could only search the public stacks. The closed stacks were off limits.’

‘But now you have access. Have you seen this thing? What is it?’