I find it kind of awkward to hide a "Show HN" entry behind a login wall, without any explaination what to expect there.

The given "static" URL is some help, but still just shows a page filled with book covers, without any explaination what this is all about.

If you don't have a Goodreads account, here's what this looks like with mine:

http://xuanji.appspot.com/static/books.html

Thanks for making it easier.