If you're just curious about octopuses, I think you can probably learn much more in much less time by doing your own research and finding articles like this.
If you're more interested in consciousness a good place to start is "Conscious: A Brief Guide to the Fundamental Mystery of the Mind" by Annaka Harris.
I'd have to give an anti-recommendation to this book. The author never explains his thesis and the book reads like his thesis was "Octopuses are cool" and spends the entire time listing fun facts and interesting stories about his interactions with cephalopods.
He spends very little time drawing connections to consciousness or speaking about what octopus life can tell us about consciousness. There is a whole chapter where he talks about the influence of language in human action (like self-talk), and then ends the chapter by with something like "and octopuses don't have this ability". What was the point of that whole chapter then?
Maybe my expectations were miscalibrated, and I thought he would spend more time drawing connections between octopuses and humans, and what those similarities could tell us about consciousness. Instead of that, the writing about consciousness in this book is quite shallow.