Introduction to ADFS 2016
While the overall purpose of this guide is to go through Azure Active Directory there are on-prem products that are related enough to warrant a mention. Active Directory Federation Services (ADFS) could be said to be a relative of AAD, and with the upcoming 2016 version, (part of Windows Server 2016), the differences between the two are further reduced. ADFS is not the same thing as having an on-prem AAD, but from a developer perspective it's starting to become easier to support both without writing a lot of code to handle the differences.
This guide will not cover everything you can do with ADFS, as that is not part of the "mission statement", but looking into some aspects of it isn't going to hurt our appreciation for the cloud :)