I will note upfront that this is a rewrite of an older post I worked up maybe a decade ago. I'm not sure if I would be able to find it again, but figured I wouldn't even bother. Better to start fresh after all this time, even though the advice I gave, from what I can remember, was sound.

Presuming you have a local library, they will likely have an annual or twice-annual booksale. Book repositories of all sorts need to refresh their inventory every so often, and that often includes discarding a lot of great books. Libraries, I will say right now, are another of those professional aspects of dealing with books that I don't have any experience with other than making use of them. I do know that there's a heck of a lot that goes on at a library that the movies either don't tell you or lie about (how many secret caverns lie underneath libraries, how many esoteric, off-limits books are there really). Either way, sometimes they need to off-load metric tons of books to make room for all the new books, all the books the local public might actually make use of.

The quality of a library book sale, in my experience, depends on the city and the size of that city and that library. A small town library may not have much, but then again you'll probably be able to pay only a dollar or two for whatever you do find. The goal of a library book sale is to move books, and to make a little money for the library. I suspect the former is the primary goal. Also, if your town or city is big enough, the library will take donations from the public of books to be sold at the sale. What this means: there will be books that are NOT ex-library with all the stampings and entombed/taped in mylar. There will be books that are basically in new condition, and some that are rare, and/or signed by the author. Often these will be set aside in some special section where books are priced individually, other times they will go entirely unnoticed until you come along and discover it.

I will be presuming the library book sale you are going to is on the larger end (scale down as needed). Before you go, have an idea of what you want to look for. What genres, what authors; are you looking for hardcovers only, or are trade paperbacks ok? Comics? Children's books? Often these sales also sell CDs, DVDs, even LPs. Know what you're interested in so you don't get too distracted by everything else. Some basics:

• Wear deodorant. There's likely to be a lot of people, and not a lot of space to shuffle around in. On a rare occasion the sale will be held outside, but in my experience that just means it's the middle of summer and sweltering.
• Bring some heavy duty cloth bags.
• Be polite and considerate!
• If you're worried about viruses, absolutely wear a mask. These days, people had better understand, even if most of them won't be wearing a mask.
• A water bottle is probably a good idea.
• If you have a little wheelie contraption you can put your cloth bags on as they fill up, that'd be super useful.
• Budget. The books may be super cheap, but it's easy to go overboard. For me, it's often been the case that the weight of the bags determines when I'm done. The bags can fill up fast, and even if the books are only a dollar or two each, that adds up quick, too.

Now that you're there and ready, how do you approach the overwhelming amount of books stacked on tables all around you? all those boxes underneath the tables just waiting to be sorted once there's room on the tables? For myself (which is a lot of what this will be), I consider what I want to avoid. There are several genres that I will avoid entirely. These days, because my place is too full of books, I have to be even more picky. These are some of the things I avoid:

• Ex-library books. I know, this is a library book sale, but like I mentioned above, libraries get a ton of donations, and I don't think they look through them very carefully. A significant portion of the books available will not be ex-library; it's not as exclusionary as you might suppose.
• Similarly, Book Club Editions (BCEs). Unless it's something I just really want to read. Otherwise, with very few exceptions, they're just not as respectable. Ok, that sounds a bit silly. But the quality of the paper used, the covers, the binding, is just not as good as a regular edition. Sometimes it is hard to tell, in which case, fine. In large part this rule is just another rule to limit what I take home with me. You may not have the same worries as myself.
• Badly damaged or soiled books, books with heavy annotation. Unless it's something super rare or that I really, really want to just read. But mostly, avoid.
• Book #3 or #8 in a series that looks really cool, but I haven't read and don't own the volumes that come before the book I'm currently looking at. Sometimes it's surprisingly difficult to tell when a book is part of a series.
• Books that use the movie poster as the cover.
• Duplicates. I am guilty of buying duplicate copies of several books. These days, I try to avoid buying more, unless I know someone I want to gift it to, or, you know, if the book is actually valuable.

To which brings me to another important point: I DO NOT GO TO LIBRARY BOOK SALES TO FIND BOOKS TO RESELL! You will encounter guys with scanners, scanning barcodes one by one. I do not understand how that's a good use of your time. I go for fun, and since I've worked with books for so long, I have built up a sixth-sense/developed a nose for sniffing out books with potential value without the need of a scanner. But again, that is very much not my primary reason for going to these sales. And also yes, I have definitely found books of value at these sales.

Honestly, I'm usually more inclined to look at the older books that don't have barcodes anyway, so pre-1970s, generally. I do love to see the mid-century books and older, too, but... older for sure does not necessarily mean more valuable, or more interesting.

Oh! and can't forget: you can become a friend of the library at many libraries, and you might be able to get in to the sale early. Becoming a library friend might entail different criteria at different locations, I don't actually know. A small annual donation, or something? And if you can prove you're a teacher, in my experience going with teachers, they get 50% off the already astoundingly low prices. And the last day of the sale could be a bag day, where you can fill up a regular size cloth bag with as many books as you can and only pay a flat price for everything.

Find the right library, go to their sales, and before you know it your home will be overflowing with books. And the ones you decide you didn't actually need? Find a local Free Little Library to put 'em in.

One last quick pro-tip: look out for hardcovers where the dust jacket has been preserved in mylar, similar to library books but without all the stickers and stamps. Somebody took special effort to preserve that dust jacket, and by extension to keep the book itself in good condition, so chances are the book was special to someone. The chances of the book being signed are much greater. The book might also be a first edition. There's always the chance someone bought it new on speculation that it would blow up and be super valuable, and there's always a good chance that neither the fact of the first edition or the signature add any value to the book at all, unless you personally are a big fan. But that's all stuff I can get into in another post, 'cause evaluating books is a strange and murky business. The great thing about these sales is that you can take a chance and not break the bank.

Support your local libraries!