Hi James and welcome
Having just finished an Android class, I am curious to know how html5 differs on that platform vs. the basic browser platforms—or are they essentially the same?
Thanks and good luck with your book
Your mileage will vary depending on the version of Android you are targeting. Cupcake/Donut/etc in the 1.x branch don't support HTML5 at all IIRC. Eclair/Gingerbread/HoneyComb and ICS (2.1+/3.0+/4.0) all do much better in terms of support.
The best guide to check is CanIUse.com. It lists the capabilities of the mobile browsers along side the desktop browsers.