I don't know why I keep on buying Jonathan Royle's products. I have 4-5 and have always been
disappointed. This is no different.
Most of what he has can be found on the Zoom website -
except his information is dated. The rest is other publications, at one is from 2016 and
copyrighted.
No new material or insight. More up-to-date information can be gathered
easily. Don't buy it.