If it required a person to "Study" from the book, that would take at least 30 days (Study -2 months lost = -2/3 study total), and then the character would have to make a roll on their newly acquired (minimal) knowledge- no thanks.
So I think it's essential that someone (of adequate Literacy) be able simply attempt to "look up" or find some fact in a text or collection of them. How? That is a more subjective question, since it is not addressed BTR.
The easiest method would be to set a Difficulty number, and then make a roll based on the Time the characters have, and the Level of the Text. This could certainly be modified based on RP considerations, such as the relationship of the actual Text, based on the breadth of its coverage. (ie, low-level books are less likely to cover "everything" than high-level.)
A Tractatus would need to be judged case-by-case, as those are written on extremely specific and narrow topics (such as a single spell, or a single example of the greater topic, such as an animal (Realm Lore) or instrument (Music), etc), and most likely either would be of great help or none at all. A Tractatus on Vampires would most likely offer little information on general Necromancy.
Quality does not affect the amount of information a book contains, but it does seem to affect how effectively a reader can absorb/gather/comprehend the information that it contains. So, it would be nice if Quality could be incorporated somehow. However, short of arbitrary rules or SG modifiers to the roll, I'm not sure how I'd approach that issue. Time and re-rolls are another issue that has to be ruled case-by-case by the SG - how much time is spent on the books to gain one roll (an hour, a week), and at what point they are "thoroughly" perused.
So, yes, it certainly can be done, and is in RL, as well as being a classic story bit, and one traditional IC purpose for having a Library (study and prestige being 2 others). But remember, most "Libraries" are nothing like present day- they're more like a small, dedicated bookshelf or two in the family den. A "huge" library might have 100 texts, equal to a couple shelves in your public library, not even one side of one short aisle. Whether the (relatively) few, limited books in your medieval "library" actually cover the topic is up to you, and/or the luck of the dice.