A free ebook on Office 365 is available to download. I have no doubt that more ebooks will come to cover all aspect of Office 365.
This one is more small business oriented but could be valuable for everyone working with Office 365.
“This book shows you how you can use cloud computing—and specifically,
Office 365—to get more done, collaborate more easily, and work more
flexibly than you ever have before. From the necessary how-tos about
creating and administering your Office 365 account and working with the
various Office 365 programs to sharing files with your team, creating a team
site, using Office Web Apps, and holding online meetings, you’ll discover how
easy it is to work online and off, accessing and sharing your files whenever
you need to. After you learn about each of the core programs, you can try
strategies for building successful teams, and get some good ideas on practical
ways you can put all this cloud power to work.”