I have this book and use it all the time. Your five star rating is right on the mark.

I only have one bone to pick. There is an error that is repeated in example code throughout the book. The sacred-to-sort package globals $a and $b are used as generic temporary lexicals. That's harmless in the examples, but it's bad practice, and it might lead to grief for a reader experimenting with the code.

After Compline,
Zaxo