This book is book great and after you've read it I can recommend "The Powershell Scripting and Toolmaking Book"[1]. I just started reading it and teaches you how to write good tools with practical examples and business scenarios. My next step will be learning Pester and DSC.
Also "Powershell in Action" by Manning is great to lookup things in detail.
Also "Powershell in Action" by Manning is great to lookup things in detail.
[1] https://leanpub.com/powershell-scripting-toolmaking