Books in prisons have proven to be beneficial for the economic and mental well-being of prisoners.  However, budgets for prison libraries in the United States have been drastically cut over the past decades, even as prison populations swell.  Books to Prisoners is a Seattle-based non-profit that provides free books to prisoners across the country; it operates on donated time, books, and money to fill the 1,200 requests sent every month.  Due to its limited resources, the organization has never created an inventory of book donations or prisoner requests to assess its own needs.  This project sampled and analyzed the content of donated books and prisoner letters.  This information was used to determine the most critical service gaps and contact appropriate publishers to solicit targeted book donations.  Books to Prisoners is now better prepared to request donations, write grants, and support a national population facing dire information shortages.