This is a great introduction to Racket as a language for building languages.
For those interested further, there is a lot of work with Racket in this respect. A recent paper previously hit the front page of HN on "Domain Specific Languages" (DSL's), which is basically the idea that you should write a programming language for each problem to make it easier to write programs in that domain rather than writing complex spaghetti code in a general-purpose language or writing a library that badly ports to the general purpose language. I'm a bit biased here, but I think this could be the next big step in programming in the next few decades as we see people not writing libraries but writing DSL's to make for easy writing of programs.
And here's a worked example of applying this approach, in this case to the domain of video editing: Super 8 Languages for Making Movies (Functional Pearl)
https://www2.ccs.neu.edu/racket/pubs/icfp17-acf.pdf
For those interested further, there is a lot of work with Racket in this respect. A recent paper previously hit the front page of HN on "Domain Specific Languages" (DSL's), which is basically the idea that you should write a programming language for each problem to make it easier to write programs in that domain rather than writing complex spaghetti code in a general-purpose language or writing a library that badly ports to the general purpose language. I'm a bit biased here, but I think this could be the next big step in programming in the next few decades as we see people not writing libraries but writing DSL's to make for easy writing of programs.
HN Discussion: https://news.ycombinator.com/item?id=16454854
The authors of the paper are mentioned in the acknowledgments of this book as well!