Start with high-confidence email administration books, then narrow by subgenre or adjacent topics.
Sendmail Cookbook
Craig Hunt
Microsoft Outlook 2016 Step by Step
Joan Lambert
Using Mac OS X Lion Server
Charles Edge
Windows Powershell Cookbook
Lee Holmes
Learn Active Directory Management in a Month of Lunches
Richard Siddaway
Learn System Center Configuration Manager in a Month of Lunches
James Bannan
Powershell in Depth
Don Jones, Jeffery Hicks
Learn Powershell in a Month of Lunches, Fourth Edition
Travis Plunk, James Petty
