I've had very good luck with Bards & Sages products in the past, but this one was, frankly, much less impressive. The problems begin already on p. 4--the first page of actual content--where the author refers to a previously unmentioned "multi-library quest" to find "the Astral Fortress." Nothing in the document prepares readers for this; all that precedes this notice is an explanation of the library stat block format used throughout the product. The author doesn't even begin to explain this "quest" until p. 36 of a 42-page product. Perhaps the author wanted the DM to "experience" the quest in a manner that mirrors the PCs' experience in visiting various libraries and assembling various clues, but as a DM seeking to use this product in a home campaign, I would call that a very poor and off-putting choice. This feature was a disincentive even to read past p. 4.
Moreover--especially egregious in a product that's supposed to be about centers of learning--the product suffers from frequently errors in spelling, grammar, usage, and mechanics. Already on p. 4, the reader encounters such mistakes as a reference to "story arches" instead of "story arcs" and the "peek times" (the correct phrase is "peak times") for library traffic. Later, readers encounter a library that has some books "for sell" (the author should have written, "for sale"). The formatting of the stat block varies from line to line, and various punctuation marks are either misplaced or missing. I counted five errors of punctuation or capitalization in the first three paragraphs alone. That sort of thing immediately removes all presumption of confidence in the quality of the work. I'm a college professor, and if a student handed in a paper with that many errors in the first three paragraphs, I would not even bother to read the rest of it; I'd give it back and insist on better proofreading and revision before spending my time trying to give it a grade.
Moreover, the author's assumptions about shelf space seem quite wrong to me. The author states that a "ten foot high, three foot wide, bookshelf can hold between 100 large tomes or 1,000 small ones" (p. 4; all grammatical errors in this quotation are in the original). I'm not sure what dimensions the author imagines for a "small tome," but I'm sitting next to a three-foot-wide bookshelf right now, and the top shelf has 31 books on it. (The thinnest is "Charlie and the Chocolate Factory"; the thickest is the "Lord of the Rings" three-in-one movie tie-in paperback). I've been in quite a few modern libraries, and I've rarely seen one with ten-foot-high bookshelves, but let's work with that for a minute. If the vertical space allotted to each shelf is about one foot, that gives you ten of those three-foot-wide shelves on which to put your library books. Ten three-foot-wide shelves gives you, obviously, a total of 30 horizontal feet or 360 horizontal inches in which to store your books. In order to fit 1,000 "small tomes" into that space, each of those "small tomes" must average no more than 0.36" thick, less than half the thickness of the D&D 4e Player's Handbook. Somehow, I just can't picture many tomes in a fantasy RPG world being quite that small. The books in the illustration on p. 7 are certainly much thicker than 0.36"! The numbers at the "low end" of the scale work fine, but at the "high end," they're way off.
I tried to hang in with Library Lore a bit longer, especially because my current D&D campaign requires the PCs to search for a particular book--and what better place to look for a book than in a library? Frankly, my esteem for the product didn't grow as I read through it. I really wanted to like this product, but it's just not very well done. The artwork and layout are unattractive and, in some ways, not very useful; for example, the subheadings within a library write-up are larger than the type that introduces each library to begin with (in the stat block). Too much of the detail given about each library ties into the "multi-library quest," an element that isn't even mentioned at all in the product description!
But what about the libraries themselves? "Arnie's Library" has an entertaining patron, but otherwise offers relatively thin story possibilities unless the DM is using the "multi-library quest" (or the PCs try to break in when Arnie's not around). "The Corner Store" offers even less if you're not using the "multi-library quest"; the proprietor serves chiefly as a vehicle for inexplicably giving the PCs a magic item. The "Echo Library" offers some very interesting possibilities, if an enterprising DM chooses to develop one of the bullet-point adventure seeds. "Gadget Hall" is rather too "steampunk" for my tastes (one of the proprietors is close to inventing the parachute?). I like the idea of the "Grass Lot," but the product focuses on developing a link from the Grass Lot back to Gadget Hall in service of the "multi-library quest" instead of enhancing one's sense of the library itself. "Grom's Library" introduces a quasi-dungeon crawl into the product. The "Halls of Steel," a dwarven mining and stonecutting library, feels awfully stereotypical. The idea behind the "House of Cards" is pretty entertaining, but following the plot suggested forces the PCs to go to one of the other libraries. Using the "Knowwood Forest" as written requires the DM to insert a "Knowwood" and a "Darkwood" into his or her campaign, a proposition that some may find disagreeable; moreover, a forest library run by elves and featuring books written on leaves is every bit as stereotypical as the dwarven mining library. Similarly, using "North Legal South Law" in your campaign requires you to import a whole bunch of the author's campaign assumptions into your own setting. The "Rainbow Paradise" is apparently supposed to be set on a tropical island, but how you get it close enough to the other libraries (which don't fit naturally on a tropical island) to make the "multi-library quest" workable--in a way that doesn't stretch the imagination too far--is a little beyond me. Finally, one gets to the "Astral Fortress," the target of the multi-library quest.
Oh, and one more complaint: there are too many dragons in this product! "Arnie's Library" involves a red dragon; some patrons suspect that the proprietor of the "Corner Store" has dragon blood; "Gadget Hall" involves a blue dragon; a half-dragon is on the staff of "Grom's Library"; a green dragon figures in one of the "Knowwood" adventure hooks; and a "redeemed" red dragon apparently lives in the "Astral Fortress." One dragon might have been okay, but this is overkill.
I had high hopes for this product and ended up very disappointed.