Microsoft Press provide a First Preview of the upcoming second edition of Kraig Brockschmidt’s Programming Windows Store Apps with HTML, CSS, and JavaScript!
The 255-page PDF itself can be downloaded here: http://aka.ms/SecondEdition/FirstPreview (5.57 MB)
FYI, EPUB and MOBI for the ebook’s final release will be provided, not for the two preliminary releases.
Also, please remember that this material is in DRAFT form. This content will not be final until the ebook’s final release.
Source: Microsoft Press Blog