Catalog says available? Go to that library to pick it up in person. Here is a list of Book Locations.
Book checked out or at the Library Service Center(LSC)? Request it by clicking on "Get this title" in the lower right corner, and then clicking "Request" under "Get it at Duke."
For more information on requesting materials check this out.
Duke Library Catalog
Start here to find books in Duke libraries. Toggle to view books available in Triangle area libraries (UNC, NC State, NCCU) in the upper left corner of book results page.
Catalog of libraries in US, Canada and beyond.
Center for Research Libraries (CRL)
A consortium of North American universities, colleges, and independent research libraries that acquires and preserves newspapers, journals, documents, archives, etc. They can be borrowed on extended loan via Interlibrary Loan.
Includes many online books - mostly older editions that are out of copyright.