The USPS has specific guidelines for sending items under Media Mail. The lists of allowed items are video tapes, film, sound recordings, books, manuscripts, CDs, DVDs and floppy or Zip discs. Magazines are not included on this list because magazines contain advertisements, and advertisements are not allowed to be sent through Media Mail. The Book Rate was mainly for books when it was first created, but if your intention is to send books to or from a library, then you should use the cheaper alternative known as Library Rate. USPS says that the packages are typically sent and received within 7 to 9 days, but this can vary by location.