Although Sarah is the main contact person for library visits, the library liaison for your subject area will be providing your tour and/or instruction.
The subject area librarian who serves as liaison to faculty in your discipline is a professional (MLS) librarian, equipped to perform subject-specific instruction for your classes, especially at an introductory level. He or she can also provide you with regular email updates on library resources pertaining to your discipline and assist you in placing orders for books and other materials. Every liaison reviews all of the available syllabi in his subject area in order to understand both classroom assignments and the materials that may be needed in the library to support the curriculum.