No story here – I don’t know the designer or the usage – I just love the thematic consistency across the posters, the clever manipulation of the same phrase, and the bold colour choices. 

Don't Settle for Half an Answer Poster
Above: “Don’t Settle For Half An Answer. Ask a Professional. Ask Your Librarian.”

Get a Clear Answer
Above: “Get A Clear Answer. Ask a Professional. Ask Your Librarian.”

Poster depicts a maze with "the answer' in the middle

Above: “Find The Answer Fast. Ask a Professional. Ask Your Librarian.“

Get Answers To All Your Little Questions Too / National Library Week (1989)

Above: “Get Answers To All Your Little Questions Too. Ask a Professional. Ask Your Librarian. / National Library Week, April 9-15, 1989″

Source: American Library Association Archives, University of Illinois at Urbana-Champaign.