I think this book is more UX, but it has a good set of basics that I can agree with.
UI Design is a subset of UX, as the UI is one (major) factor that shapes the user's experience of your product.
So saying 'this book is more UX' somehow implies UX and UI are separate - which they are not.
This book covers several UX disciplines, including some UI design tips.
Well, UX and UI often goes together. I like more to talk about "interfaces" in general.
Pure UX for me is making research, personas, usability testing and all that.