Two books for SharePoint 2016. Basic concepts do also apply for sites, libraries and lists in Office 365 but visual appearance will differ.
SharePoint 2016 User’s Guide
Learning Microsoft’s Business Collaboration Platform
Authors: Smith, Tony
Comments: This is a good reference for site owners and contributors, lots of detail
Microsoft SharePoint 2013 Plain & Simple
By Johnathan Lightfoot, Michelle Lopez, Scott Metker
Part of the Plain & Simple series.
From Microsoft Press
Comment: This is a picture book for SharePoint, surprising amount of content