Skilled and knowledgeable librarians are assigned to each school, several departments, centers, and organizations. You can find your liaison and his / her contact information here: http://guides.lib.uw.edu/hsl/liaisons
Liaisons are happy to meet with students, faculty, and staff and are generally on premises from 8:00 to 4:00 Monday-Friday. though they have teaching obligations throughout the day.
Staff at the 3rd floor Information Desk are happy to answer questions as well.