One of the issues to be faced when discussing the “reference librarian” as a profession lies in defining “knowledge.” It’s become an exceedingly slippery word.
1. acquaintance with facts, truths, or principles, as from study or investigation; general erudition: knowledge of many things.
2. familiarity or conversance, as with a particular subject or branch of learning: A knowledge of accounting was necessary for the job.
3. acquaintance or familiarity gained by sight, experience, or report: a knowledge of human nature.
4. the fact or state of knowing; the perception of fact or truth; clear and certain mental apprehension.
5. awareness, as of a fact or circumstance: He had knowledge of her good fortune.
6. something that is or may be known; information: He sought knowledge of her activities.
7. the body of truths or facts accumulated in the course of time.
8. the sum of what is known: Knowledge of the true situation is limited.
9. Archaic. sexual intercourse. Compare carnal knowledge.
I think we can ignore the last.
Interestingly, when you look for “knowledges” you find no definition … though this was once a word (I picked it up from Francis Bacon) that seems to have gone out of common use in the early 19th century … leastways as far as I could determine. It’s related to #6 above. It’s the things one can know in the various “fields of knowledge” that comprise our world. The content of what we broadly label “biology,” “politics,” “religion,” etc. are the knowledges that appertain to each.
In another way of looking at it, “knowledges” are what are “knowable.” And the latter (and here I’m following the lead of various “knowledge managers”) is a reflection of an internal state. Books, etc., do not contain knowledge.
People, however, do and it can be argued that some automata might.