I would knock a half a star off for some weakness in the index. That's a particularly big deal in a reference book. But it's not bad.

Overall this is a must-have. Holmes clearly knows his subject and presents it well. (He is a member of the PowerShell Development Team.) I may actually read this "reference" book. The quality is far and away superior to the other O'Reilly Pocket Reference books I've purchased. They gather dust on my shelf.

The content is substantial. Weighing in at 174 pages it dwarfs many O'Reilly Pocket References, yet is still highly portable.

Everyone knows that PowerShell users will want to read Windows PowerShell in Action for deeper understanding. I also like Windows PowerShell Cookbook: for Windows, Exchange 2007, and MOM V3 (also by Holmes) for examples that frequently help me get things working. Whatever else you get, you should have Windows PowerShell Pocket Reference.