Superstar Bruce Payette is writing a book focused on the whats and whys of the language called PowerShell in Action. Bruce is the dev lead on the language and is a walking encyclopedia of computer languages. I have the honor of being a technical reviewer of the book and it has me jumping out of my chair with excitement (seriously, when you grok the full power of this tool – it just blows the top of your head off). Bruce puts this in a context that just makes everything so clear. This will be the book that takes beyond the basics and gives you a full understanding of the amazing capabilities of PowerShell.
Anyway, you are going to want to watch for this book when it comes out this fall. You can get a sneak preview (the cover and Chapter 1 online) at: http://www.manning.com/payette/
Check it out!