From .NET Core in Action by Dustin Metzgar

Learning a new development framework is a big investment. You need to learn how to write, build, test, deploy, and maintain applications in the new framework. As a developer, there are many frameworks to choose from and it’s difficult to know what’s best for the job. Even if you’re currently developing software with .NET, .NET Core is different enough that you’ll need to spend time learning the tools and techniques to use it properly. To understand why .NET Core is worth a look,it helps to know where you’re starting from.