While the topic of Microsoft Graph is very interesting, it's also fairly large, and this book wouldn't be able to accommodate everything there is to know about this service.
In simple terms, Microsoft Graph is a unified platform that offers a single endpoint for accessing Office 365 and certain Microsoft Azure services including Microsoft Azure Active Directory (Azure AD). This removes the need for developers to learn multiple different APIs, where typically each API acts a little bit differently from each other, depending on the service they communicate with.
The benefit of using Microsoft Graph is evident; by authenticating with Microsoft Graph, a developer can create code that can easily access most major Office 365 services, including SharePoint Online, OneDrive for Business, Exchange Online, and Office 365 Groups. In addition, Microsoft Graph also provides visibility to Azure Active Directory-stored entities, such as users and groups, individual...