It is explained in the passage that any book which is not available in one library _.

Public libraries, maintained by the local
authorities, are well developed and progressive,
and everywhere allow people to borrow books
without charge. The books in the lending section
are always kept on open shelves, and library
staffs are very helpful in getting books on equest
from other libraries through the exchange
system. Most libraries report an increase in
borrowing over the past few years, so television
does not seem to be stopping people from
reading, so it was feared that it would.