Easy to use and an excellent complement to libby. Found via Cory Doctorow's blog at pluralistic.net. adversarial interoperability at its finest!

This extension is probably the most useful one I have, aside from an ad-blocker. It is so easy to add my libraries, and it saves a ton of time instead of searching in each catalog. Highly recommend!

Magnificent add-on. Wish I'd have found it sooner.

Works very well except for one quirk: It refuses to save my library info between FF sessions. I can enter the info and so long as I keep a FF session open the info is retained so I will see if my library has a book I am looking at in AMZ or B&N etc. But as soon as I completely close all FF sessions the info is lost and needs to be reentered the next time I need it. Yet this same problem does not occur in the chromium version. This is very annoying because FF is my primary browser for 99% of usage, I use chromium based ones only when required by other software or sites.

If they fixed this quirk this would be a 5* rating.

Absolutely brilliant stuff, and unthinkably convenient for something I'd never stopped to consider the possibility of. Earnestly recommending this to everyone I speak to from now on.

Super-useful integration with OverDrive to save money.

Very helpful to see which books are available at my library, but it apparently only looks at title, not author, because I've gotten several hits for books with the same title but not the same book.

Makes everything much more streamline when trying to find books!

I love it so much, but I wish there was a feature for when a book isn't available in your library to send a message asking if they can add it to their collection.

I have 10 or so different library cards, and Library Extension is so incredibly helpful. I love being able to see at a glance whether a certain book is available from any of my libraries, or how long the wait will be. Favorite extension ever.

Saves a lot of time searching library catalogues! Very quick to respond to issues, too.

This add-on is so convenient. I love being able to set the libraries I want to search and have that search performed automatically.

It is very convenient to use and makes finding a book so easy. They have graciously added the 2 military libraries I deal with in a quick response. Plus I am able to find libraries as I travel. Thank you so much!

An absolute lifesaver! It's made getting books from my libraries so much easier. See a book you are interested in? It tells you right there if its at your library, if its available and what formats they have it in. Perfection!

Excellent app and it works great. Libraries have a ton to offer these days and this makes it easier to access those offerings. And it will help you save money too.

The public library offers fantastic value for everyone and this extension brings it into everyday web browsing. Highly recommended!

Excellent extension! So nice to grab an ebook from my library instead of purchasing one.