Scout's greatest fantasy centers on one day actually seeing her reclusive neighbor, Boo Radley, in the flesh. "... I still looked for him each time I went by." She imagines carrying on a real conversation with him:

"Hidy do, Mr. Arthur," I would say.  (Chapter 26)

But she doesn't believe that day will ever come: "It was only a fantasy." She and Jem had seen Boo's shadow, and "We had almost seen him a couple of times, a good enough score for anybody." And on that fateful Halloween night when Scout is forced to play a ham in the school pageant, she again passes by the Radley house without ever expecting to see Boo. But Boo does finally appear before her: first on the trail home from the school where Boo saves Jem and Scout from Bob Ewell; and then inside the Finch house where she finally realizes that the silent man standing "in the corner" is actually Boo.

He had been leaning against the wall when I came into the room...
When I pointed to him, his palms slipped slightly... but as I gazed at him in wonder, the tension slowly drained from his face. His lips parted into a timid smile, and our neighbor's image blurred with my sudden tears.
     "Hey, Boo," I said.  (Chapter 29)
     "Mr. Arthur, honey," said Atticus, gently correcting me.  (Chapter 30)

Boo and Scout spend more than a few minutes together: They sit side-by-side on the porch, she leads him into the bedroom where he pats Jem on the head; and then she escorts him home and sees him inside. "I never saw him again."