You must overcome any shyness and have a conversation with the librarian, because he [sic] can offer you reliable advice that will save you much time. You must consider that the librarian (if not overworked or neurotic) is happy when he [sic] can demonstrate two things: the quality of his [sic] memory and erudition and the richness of his [sic] library, especially if it is small. The more isolated and disregarded the library, the more the librarian is consumed with sorrow for its underestimation. A person who asks for help makes the librarian happy.
Although you must rely on the librarian’s assistance, you should not trust him [sic] blindly. Listen to his [sic] advice, but then search deeply and independently. The librarian is not an expert in every subject, and he [sic] is also unaware of the particular perspective you wish to adopt for your research. He [sic] may deem fundamental a particular book that you end up barely consulting, and may disregard another that you find very useful. Additionally, there is no such thing as a predetermined hierarchy of useful and important works. An idea contained almost by mistake on a page of an otherwise useless (and widely ignored) book may prove decisive for your research. You must discover this page on your own, with your own intuition and a little luck, and without anybody serving it to you on a silver platter.
Umberto Eco (January 5th 1932, Alessandria – February 19th 2016, Milano) How to write a thesis (1977) pp. 56-7