"Not much, except that they are a sort of parasitic group, living
usually in a servant relationship to other races on terran-type worlds.
As I recall, even they claim that they do not know the planet or even
the galaxy of their origin, because they have been wanderers for so many
generations among alien races. Perhaps it would be a good idea to make a
study of them, too--I don't know that a thorough one has ever been
made."
"That's what I wanted to warn you about," said Fothergill, smiling.
"Stick to one subject at a time. The Ids _would_ make a nice research
project in themselves, and maybe you can get around to it eventually.
But leave them alone for the present and don't become distracted from
your basic project among the Markovians. The policy of the Corning
Foundation is to demand something very definite in return for the money
they lay on the line. You won't get to go back next year unless you
produce. That's why I don't want you to get sidetracked in any way."