Reference material you can dip into while working through the main chapters.
The appendices are meant to be practical reference, not required linear reading. Use them when you want a fast refresher on syntax, tooling, or terminology—especially when you are actively coding and do not want to break your flow by searching elsewhere.
If you are early in the track, skim the cheat sheet once, then return to it whenever you hit unfamiliar forms or core functions. If you are already writing Clojure in a real project, the appendices work well as a “check your assumptions” layer.