The book can be viewed here: http://addyosmani.com/essential-design-patterns
I've had a number of readers get in touch about ePub/Kindle/other formats of the book and I'm currently working on these. Because the content is being updated every week or two, we'll probably need to get a build process in place to automate the book conversion but I'll announce on Twitter as soon as formats can be downloaded.
A Physical Version Of The Book
Update: Version 1.5.x of the book and above are available in either online form to read for free or via O'Reilly if you'd like to pick up physical or eBook formats of the book. The latter is a lot more visually pleasing than the PDF/eBooks I used to generate and I hope this combination of free or purchase options satisfies most readers needs.
One thing I hope comes out of this is that if anyone in the community notices a section of the book that could be improved (whether it be a typo, a grammatical issue or just something that could be done better) all I ask is that you let me know so that I can address it for a future version. I'm more than happy to accept feedback via the comments below or via the issue tracker on GitHub.
That's it. I hope that the book comes in useful and helps encourage you to explore the wonderful world of design patterns just a little bit further. Again, feedback is always welcome and appreciated!.