In this book, which is the second in the series Unity from Proficiency to Mastery, you will get to master C# and how it is used in Unity for common game mechanics; you will also learn how to optimize your code and make it more maintainable over time.
This seems like a decent crash course to the very basics of C# in Unity and in general. Now, the fact that this is in the series "Unity from Proficiency to Mastery" threw me off a bit and I was expecting some advanced topics from it, which is why I only skimmed through the book quickly to see what's there.