ISBN. You can link to a work page on LibraryThing just by throwing the ISBN into the URL. Examples:
Sloppy title. You can also link to a book's work page by putting the book's title in the URL. Spaces can be represented by underscores, + signs, or even simply as spaces (more here). Examples:
We have a number of very large periodic data feeds available:
What do you want?
If you'd like something we don't already have up here, or if you have any questions about the available APIs, email Tim at timlibrarything.com.
What's an API?
APIs are ways for one computer to talk to another, simple ways of getting and giving data without having to share programming code.