I have no voice but I can teach you all there is to know.
I have spines and hinges but I am not a door.
Once I've told you all, I cannot tell you more.
What am I?
Answer: A book.
This riddle appears in the following downloadable PDF files:
Can you solve one of the most famous logic puzzle ever?
Memory Matching game for kids, adults and seniors.
Connect the matching tiles and pop them all.