Stack Overflow used to run an interesting project – Stack Overflow Documentation. It is currently shut down, but thanks to it we now have interesting free books like “PowerShell™ Notes for Professionals book“:
Please keep in mind it was created by SO content that may not be very accurate, like what I’d recently discovered:Are the cmdlets in a pipeline executing in parallel?
Anyway I’d recommend it since it contains an essentials compilation of PowerShell common tasks and language specifics.Good reading indeed!
There are also other books that may catch your interest:http://books.goalkicker.com/