Book is a source of communication between reader and writer. It is the main and basic material that provides complete information to the learner.

It is a set of collection written, printed, or blank sheets, or other materials, usually fastened together to hinge at one side.

But Robert makes funny guns with different books. He belongs to US and professionally mathematician. These are terrific gun models no one can easily make them.  You should see the art and make your moments full of happiness and joy.