It might be a cool book but it describes an outdated way to write compilers, even if you’re writing compilers for functional languages

What does that mean?

The book introduces how to turn a program to CPS, why you can and how that allows to compile. That’s interesting in and of itself as a way to conceptualise how a program computation flows work and what it means for the construction of functional programs.

It was never a popular way to write compilers but academic books are not tutorial. That never was the point.