I've liked most of what Mr. Woolcock has done, including this product.
I was unfortunate enough to find out that Android/Chrome does not handle PDF layers very well. I posted a question on 06/24/19 asking if it could be possible to post a layer-less version of this book for those of us that tend to use mobile devices. And within 24 hours, he uploaded a layer free version!!
Just another example of why this writer has such a loyal fan base!
[5 of 5 Stars!]