The whole phone book chapter of Purescript by example is a lot less sure-footed that the first.
The example isn't all that great with assumptions about the data and what you should be able to do with it.
It introduces Lists and Maybe but doesn't really explain how they work (and the module documentation is cryptic, really nothing more than the function signatures (*so Haskell)).
Instead it goes into how to use pointfree functions and coding style, which is amazing but still, you haven't actually explained how one is meant to get a value out of Maybe.