New to android

Hi I am new to android and I was thinking to get to know a bit about android using the book, Hello Android 3rd Edition.
I know that Android is constantly being updated.
My main question is the 3rd edition covers android versions 1.5 to 2.2, so is there any necessity fr me to learn about the previous versions or is it ok if I start directly from 1.5?
I mean will I miss anything important if I do that.
Thank you.

I am not sure what the size is of the pre-1.5 Android market, but if I recall correctly it was the 1.6 release that caused Android to take off. So I would not worry about coding for any releases earlier than that.

Thanks a lot for the clarification Peter

For anything you're starting now I would not bother to support versions below 2.1: http://developer.android.com/resources/dashboard/platform-versions.html