This book states at the beginning that it's not a standalone resource - you'll need to read the official Oracle Tutorial at least, but that it supplements all other learning. I'm finding it hard to see how it supplements my prior learning in any meaningful way.
The layout is very basic. There is no colour to aid revision and no touch-points to zone in on. Just a lot on black writing. In addition to this basic design there are a large number of spelling mistakes, which really irritates me. Little has been done to edit this book - it feels like it was thrown together and published at pace, and never picked up again.
The only saving grace is that the website mentioned is pretty helpful.
EDIT: Just scraped through my exam and can confirm this book didn't help me at all. There was a large number of topics covered in the exam that aren't focused on in this book. My recommendation would be to buy the Oracle textbook and learn it extensively. Review down from 2 stars to 1.