How do I send an inmate a book (I use Amazon or CBD). Do I use the PO or street address?

Depending on the facility, it is usually the PO Box for inmates. You can go to the Prison Directory on InmateAid and search that facility page for the "Mailing Address". If one is not listed, use the main address. That is how we sync our mail system to send Letters & Photos, Postcards and Greeting Cards directly to the inmate.