What does Jonas notice that is unusual about The Receiver in The Giver?

Jonas notices that the Receiver is the only one with books.

Jonas makes a lot of observations about the Receiver.  He notices that he seems very old, and that he is usually apart from the rest of the community.  He does not take part in most community events.  Before being selected as the new Receiver, Jonas is only vaguely aware of who he is.

The Receiver was the most important Elder. Jonas had never even seen him, that he knew of; someone in a position of such importance lived and worked alone. (Ch. 2)

Jonas notices that the man, “a bearded man with pale eyes,” is watching him during the ceremonies. Of course he came to that ceremony, because it was the one were his successor would be announced.  He wanted to be there when Jonas was selected, and watch him.

When Jonas begins his training, he notices that the Receiver’s quarters are very different.  The furnishings are unique, and the dwelling itself is isolated.  There is also something else very different about the Giver’s quarters.

But the most conspicuous difference was the books. In his own dwelling, there were the necessary reference volumes that each household contained: a dictionary, and the thick community volume which contained descriptions of every office, factory, building, and committee. And the Book of Rules, of course. (Ch. 10)

It makes sense that the community would not have books.  After all, they have no sense of history so the past can’t be written down.  The community does everything it can to isolate its people in a continuous present.  This is why they keep the past in the Receiver of Memory.  One person contains all of the community’s memories so that they do not make mistakes made in the past.

The books help Jonas realize that he is definitely in a different world now.  It is the first sign that things are not what they seem in the community.  Why would one person have books that no one else is allowed to have?  As Jonas continues his training, he learns that there is definitely more to the community than he ever realized, and he learns what the community is hiding.