"It's part of my overall interest in neural nets," Cainen said. "I'm not particularly interested in human brains, as you say. All brains are interesting in their way."

"If you say so," Sagan said. "But whatever it was you were doing down there, it was important enough that the Eneshans would rather see you and your crew dead than in our hands."

"I told you," Cainen said. "We were their prisoners."

Sagan rolled her eyes. "For a minute, let's pretend we're both not stupid, Administrator Cainen," she said.

Cainen moved forward, leaning closer to Sagan from across the table. "What kind of human are you?" he asked.

"What do you mean?" Sagan said.

"We know there are three kinds of human," Cainen said, and held up his fingers, so much longer and more articulated than human fingers, to count off the variations. "There are the unmodified humans, who are the ones who colonize planets. Those come in varying shapes and sizes and colors—good genetic diversity there. The second group is the largest part of your soldier caste. These also vary in size and shape, but to a far lesser extent, and they're all the same color: green. We know that these soldiers aren't in their original bodies—their consciousness is transferred from bodies of older members of your species to these stronger, healthier bodies. These bodies are extensively genetically altered, so much that they can't breed, either between themselves or with unmodified humans. But they're still recognizably human, particularly the brain matter.