Who is Monk from The Age of Wire and String and what is their importance?

Monk is a dog that was the Marcus family pet. He was smashed, and young Ben's father said Monk had to go to the other side of the bird (which is the sky) to get fixed. The boy kept Monk's hair in the bottom of his blanket. He wanted to stitch the hair back on the dog, and did not get to say good-bye to Monk.