As I mentioned in my about page, I'm a librarian. One tool that we use that is free to anyone is WorldCat. I don't know if many people know about it, so here's how it works.
With WorldCat, you can do one search that checks every library that is registered with the system, which is free and used by many libraries for inter-library loan and other things. WorldCat can be a little confusing- anything with that much data is likely to be confusing- but if you are a Serious Reader, it's worth trying.
WorldCat doesn't just search books. It also searches movies, articles, audio materials, and some special collections. So, for a student trying to do research, this could be great. For the purposes of this post, though, I'm talking about using it for pleasure reading.
I'm assuming that anyone reading this has a library card; if not, you need a library card. You can very likely have more than one card. That's where WorldCat comes in.
Let's say that you're looking for a book. I'm going to use The Virago Book of Ghost Stories as an example. (I love this book, BTW. I have a copy, but I was going to buy one for my library recently, and it's hard to find now, so that's why it's on my mind).
If you search this book in WorldCat, the first hurdle is that you see that there are many editions. (I love that they keep re-issuing this book; it's a fantastic collection.) So, the first thing to do is to choose one to search. For a scholar, this is a big deal; for someone who just wants to read a book, probably just pick the most recent. If you want to track down a specific issue because you read the introduction once ten years ago and really want to read it again, then you have to pick through and find the right one.
So, once you choose one to search, WorldCat will show you all the libraries that have that book, starting with the location nearest you. This is where it's helpful to people with multiple cards. Say you have a card in two counties and one college library. This will check all of them at once.
If none of the libraries that you are a member of have the book, but you see it in another library in your region, it is very likely that your library will be able to borrow it from this other library. There are exceptions for things like brand new or rare books. You don't have to do this search yourself, but if you are intense about your nerdiness and want to know how many libraries have copies of this book and how far away from you those copies live, this is how to do that.
I've never signed up for WorldCat with a personal account, but they have that option now. Registered users can make lists and review books.
Now you, too, can use this secret librarian tool :)