What does Faber mean when he says that books have "pores"?

Faber means that books have a life all their own.

Do you know why books such as this are so important? Because they have quality. And what does the word quality mean? To me it means texture. This book has pores. It has features. This book can go under the microscope. You'd find life under the glass, streaming past in infinite profusion. The more pores, the more truthfully recorded details of life per square inch you can get on a sheet of paper, the more `literary' you are.