Our Friends purchased books for us. Do we count the revenue?

Generally no.  If a group, or the Friends, give the library cash, and you have control over spending the cash, then the funds would be counted as "Other Revenue."   If they keep control of the cash, and present you with books, or other items, then do NOT count anything as revenue or expenditure.   The value of in-kind donations is not counted as either revenue or expenditure.