I skimmed through the CAA Skyway Code. Parts are very relevant if you want to make your simming more like IRL. As a PPL of many years ago, it made me aware of how much has changed and become more complicated.
I have the book and do refer to it often. Whilst I haven't yet tried any of the exercises yet but the beauty of the files is that weather appropriate for the lesson. Alas the files will not be compatible with MSFS 2020.
I think some technology has advanced quite a lot since the book was published.