thanks for mentioning this. I'll add information to the book updates.
.NET Core is now released (also version 1.1 of .NET Core), but the tools are not. What you see with "1.0.0-preview2-003121" is preview 2 of the .NET Core tools. You can have multiple versions of the tools installed on your system. Using global.json you define what tools version is used with the project.
you can see that preview 2 is the actual version for Visual Studio 2015. For Visual Studio 2017, preview 3 is available.
Be aware that Visual Studio 2017 changes the project file format from project.json to csproj. With the release of Visual Studio 2017, the change should be smooth: opening .NET Core projects will be automatically migrated to the new format. After the migration, you can no longer open the .NET Core projects with Visual Studio 2015.
Visual Studio 2017 will be released in 2017. With the upcoming changes I'm preparing 2 PDF files that you can download as soon as Visual Studio 2017 is in a more complete state and the chapters are completed.
Also, check https://github.com/ProfessionalCShar...ssionalCSharp6
for updated source code. For Visual Studio 2017, I'm working on the vs2017 branch to have the source code available for Visual Studio 2017 without the need for a migration.
Hope this helps.