A bibliographer, in the technical meaning of the word, is anyone who writes about books.
From the en.wikipedia.org
For several years professor Donald James Winslow of the University of Boston was the magazine's bibliographer.
From the en.wikipedia.org
I cherish, as I cherish chronic dyspepsia, some of the reviews of my work that have been put together by my own American bibliographer.
From the guardian.co.uk
He was one of the seven founder members of the Pre-Raphaelite Brotherhood in 1848, and became the movement's unofficial organizer and bibliographer.
From the en.wikipedia.org
His erudition on such matters is probably considerable, since he is a freelance writer on erotic literature, and worked briefly as a bibliographer at Kinsey's Institute of Sex Research.
From the time.com
Early in his career he met the leading printer and bibliographer of the day, William Blades, from whom he acquired a lasting fascination with the printing and typefounding crafts.
From the en.wikipedia.org
Bibliographer Alfred W. Pollard named those editions Bad quartos, and it is speculated that they may have been produced, not from manuscript texts, but from actors who had memorized their lines.
From the en.wikipedia.org
More examples
Someone trained in compiling bibliographies
A bibliographer is a person who describes and lists books and other publications, with particular attention to such characteristics as authorship, publication date, edition, typography, etc. The result of this endeavor is a bibliography. A person who limits such efforts to a specific field or discipline is a subject bibliographer."