Search for free eBooks from the Google Books collection

I & my wife have a fascination for Web APIs that return results in JSON or JSONP format. We wrote a web app that simplifies the process of downloading ebooks from the Google Books collection that are free using the Google Books API after we noticed that Google Books doesn't readily show if a out of copyright book is available for free download in PDF or EPUB format. You have to go through multiple steps using Advanced Search to find this.

Luckily, Google provides a Google Books API that exposes this information and it returns the results in JSON format so anyone can build a interface to access just filtered details.

Though the books are free & old, they are invaluable, especially if you love books. You may not be able to get a physical copy of some of them even if you wanted to. Here is a list of books that I found and liked.

The H5BP template's view for Mobile

The app uses a responsive HTML5 Boilerplate template generated using Initializr.

Some other interesting things we discovered while building this app:

• Results returned by Google Books API may vary by country. When a programmatic request is made to their book search API via the app, the same code will return different results for different countries. 
• Project Gutenberg doesn't have an API but they provide one huge file that contains the RDF data for all books. 
• Open Library has a RESTful API that provides useful information about books.
• Calibre is free and open source e-book software that can convert ebooks into many formats 
• Flipkart lets you download over 9000+ ebooks for free but you will need their app to view. 
• Programmable Web maintains a directory of Web APIs & tracks news about mashups built using those APIs. The site is a treat for developers who like Web APIs & creating mashups.