In this introductory chapter, you saw a brief but high-level summary of what has changed in .NET Core 2 and ASP.NET Core 2, compared to previous versions. Now, you are also aware of .NET Standard 2 and what it is for.
We showed examples of some of the new features available in C# 6 and C# 7. These can be very useful in letting you write more with less and in making your code more readable and easier to maintain.
Finally, we touched upon JavaScript as it is ubiquitous, and this is a book about web apps after all. Moreover, this is a book on general web application performance improvements, and many of the lessons are applicable regardless of the language or framework used.
In the next chapter, you'll see why performance matters and learn how the new .NET Core stack fits together. We will also see the tools that are available and learn about hardware performance with a graph.