'The whole world?'

'Of course, when I say one of dem, I mean a big one of dem.'

'It'd have to be, yeah.'

'Like... really big.'

' 'S funny, but... I see what you mean.'

'Makes sense, right?'

'Makes sense, yeah. Thing is...'

'What?'

'I just hope it never goes plop.'

But this is the Discworld, which has not only the turtle but also the four giant elephants on which the wide, slowly turning wheel of the world revolves.

There is the Circle Sea, approximately halfway between the Hub and the Rim. Around it are those countries which, according to History, constitute the civilized world, i.e., a world that can support histor-ians: Ephebe, Tsort, Omnia, Klatch and the sprawling city state of Ankh-Morpork.

This is a story that starts somewhere else, where a man is lying on a raft in a blue lagoon under a sunny sky. His head is resting on his arms. He is happy - in his case, a mental state so rare as to be almost unprecedented. He is whistling an amiable little tune, and dangling his feet in the crystal clear water.

They're pink feet with ten toes that look like little piggy-wiggies.

From the point of view of a shark, skimming over the reef, they look like lunch, dinner and tea.

It was, as always, a matter of protocol. Of discretion. Of careful etiquette. Of, ultimately, alcohol. Or at least the illusion of alcohol.

Lord Vetinari, as supreme ruler of Ankh-Morpork, could in theory summon the Archchancellor of Unseen University to his presence and, indeed, have him executed if he failed to obey.

On the other hand Mustrum Ridcully, as head of the college of wizards, had made it clear in polite but firm ways that he could turn him into a small amphibian and, indeed, start jumping around the room on a pogo stick.