lapses in ethics and politics, Mundania has progressed remarkably in the past few centuries, thanks to the numbers of people who have made discoveries and spread information; in many respects it is a far more civilized region than Xanth. Unfortunately, the Mundanes' powers of combat have also progressed. This you will have to take on faith, for I have no way to prove it here. Mundania has weapons that are easily capable of eradicating all life in Xanth, regardless of the Shield.'
'That's a lie!' Bink exclaimed. 'Nothing can penetrate the Shield!'
'Except perhaps the three of us,' Trent murmured. 'But the main restriction of the Shield is against living things. You could charge through the Shield-your body would penetrate it quite readily-but you would be dead when you got there.'
'Same thing.'
'Not the same thing, Bink! You see, there are big guns that throw missiles which are dead to begin with, such as powerful bombs, like your cherry bombs but much worse, preset to explode on contact. Xanth is a small area, compared to Mundania. If the Mundanes were determined, they could saturate Xanth. In such an attack, even the Shieldstone would be destroyed. The people of Xanth can no longer afford to ignore the Mundanes. There are too many Mundanians; we can't remain undiscovered forever. They can and will one day wipe us out. Unless we establish relations now.'
Bink shook his head in disbelief and incomprehension.
But Trent continued without rancor. 'Now, the Xanth internal aspect is quite another matter. It poses no threat to Mundania, since magic is not operative them. But it does pose an insidious but compelling threat to life as we know it in Xanth itself.'
'Xanth poses a threat to Xanth? This is nonsense on the face of it.'
Now Trent's smile was a bit patronizing. 'I can see you would have trouble with the logic of recent Mundanian science.' But he sobered before Bink could inquire about that. 'No, I am being unfair to you. This internal threat of Xanth is something I learned just in the past few days from my researches in this library, and it is important. This aspect alone justifies the necessity of preserving this castle, for its accumulated ancient lore is vital to Xanth society.'
Bink remained dubious. 'We've lived without this library for eight centuries; we can live without it now.'
'Ah, but the manner of that life?' Trent shook his head as if perceiving something too vast to be expressed. He got up and moved to a shelf behind him. He took down a book and riffled carefully through its creaking old pages. He set it down before Bink, open. 'What is that picture?'
'A dragon,' Bink said promptly.
Trent flipped a page. 'And this?'
'A manticora.' What was the point? The pictures were very nice, though they did not coincide precisely with contemporary creatures. The proportions and details were subtly wrong.
'And this?'
It was a picture of a human-headed quadruped, with hoofs, a horse's tail, and catlike forelegs. 'A lamia.'
'And this?'
'A centaur. Look-we can admire pictures all day, but-'
'What do these creatures have in common?' Trent asked.
'They have human heads or foreparts-except the dragon, though the one in this book has an almost human shortness of snout. Some have human intelligence. But-'
'Exactly! Consider the sequence. Trace a dragon back through similar species, and it becomes increasingly manlike. Does that suggest anything to you?'
'Just that some creatures are more manlike than others. But that's no threat to Xanth. Anyway, most of these pictures are out of date; the actual creatures don't look quite like that any more.'
'Did the centaurs teach you the Theory of Evolution?'
'Oh, sure. That today's creatures are evolved from more primitive ones, selected for survival. Go back far enough and you find a common ancestor.'
'Right. But in Mundania creatures like the lamia, manticora, and dragon never evolved.'
'Of course not. They're magic. They evolve by magic selection. Only in Xanth can-'
'Yet obviously Xanth creatures started from Mundane ancestors. They have so many affinities-'
'All right!' Bink said impatiently. 'They descended from Mundanes. What has that got to do with your conquering Xanth?'
'According to conventional centaur history, man has been in Xanth only a thousand years,' Trent said. 'In that period there have been ten major Waves of immigration from Mundania.'
'Twelve,' Bink said.
'That depends on how you count them. At any rate, this continued for nine hundred years, until the Shield cut off those migrations. Yet there are many partially human forms that predate the supposed arrival of human beings. Does that seem to be significant?'
Bink was increasingly worried that Chameleon would foul up, or that the castle would figure out a way to neutralize the cherry bombs. He was not certain that Castle Roogna could not think for itself. Was the Evil Magician stalling to make time for this? 'I'll give you one more minute to make your case. Then we're going, regardless.'
'How could partially human forms have evolved-unless they had human ancestors? Convergent
