What Mater Saw

Months ago I got a set of stickers that I thought might make a gift for a child. I wanted them this afternoon, and I hunted high and low; but the safe place in which I had put the stickers was extraordinarily safe, and I could not find them.
Given that logic and reasoning and looking in all the normal places had not worked, I decided to ask my mother.
"Do you," I asked, "know where the stickers are?"
Thousands of miles away, Mater hummed a bit, and thought a bit.
"Do you even know what stickers I'm searching for?"
"Shush," Mater said. "I'm looking."
"They are on a shelf," she said slowly.
"A shelf? What sort of a shelf?"
"A shelf with a lot of books," she said.
"We have a few hundred books. Be a trifle more specific, if you don't mind."
"I see a blue book."
"A blue book. Good, good. That helps to narrow it down."
"A blue children's book. Hardback. There you will find the stickers."
I thanked her, and scampered off to have a look see.
I tore out every blue, hardbacked children's book on the shelves. I did not find the stickers.
Sometimes mothers bluff, and sometimes we daughters know that they bluff, but in the meantime, it never does a bit of harm to double check, in case bluff and luck should cross paths and the stickers emerge from the depths of wherever they have been hidden.
In any case, I can always ask again tomorrow.