Book search API?

Question

I'm looking for some sort of public API I can use to look up information on books based on title, author, ISBN, etc. I want the users of my application to be able to look these things up in the application.

Do you know of such any such API?

Update: Some other application requirements that I just thought of...I need the ability to pull up an image of the book cover. This application will mostly work with textbooks, so I will also need to pull up recently published textbooks and know the edition.

Answer 1

http://isbndb.com/docs/api/

or AsinSearch, AuthorSearch, etc using Amazon's web service.

Answer 2

You might want to check out the Google Book Search API

http://code.google.com/apis/books/

edit

In response to your edit: The google book search API includes links to image thumbnails for the books.

Answer 3

Open Library API.

Answer 4

There's also an Amazon Search API. You have to sign up as a developer on their Amazon web services site. I think that the Usage Requirements only let you use this API if the sole purpose is for displaying an advertisement and a link to buy the book from Amazon. I could be wrong about this, but this would make it unusable for my purposes.

There is a PHP wrapper for this API by using the Zend Framework Zend_Service_Amazon class.