How beautiful it is to be lost while reading a book. As someone who is also a bookworm it is really a joy for us to find and reconnect again with our lost heart and soul while we are reading. But it is also sad when you realize that in no time we will now finish reading a certain book and it feels like we are losing a great companion again. I also like your realization that: "It is a silent friend that neither argues nor complains, but always teaches."
It is true that if we can have a friend who will teach us profoundly it will always be a BOOK.