The Android book?  Just got it this week.  Been slammed at work.  I've got the basic structure for like 20 apps laid out. :)  I'm really impressed with the platform, especially the ability to call Activities from other apps without having to load the whole external app.  I've never seen OO embraced in this manner.  The memory management is quite ingenious.  For example, if you have a list of items that need to be displayed, instead of allocating space for all the display objects in memory, Android only allocates the number of display objects that can be seen at a given time.  As an item scrolls out of sight, that display object's properties are changed, it is moved to the bottom/top(depending on the direction of scroll) and reused.  So you could have 100 items to display but only need 8 display list item object in order to display them.

More to come. :)