Enjoyable read. Having just completed my bachelor's, this book is in the adjacent possible of books I should read to continue my education. The book is an easy read and doesn't feel like a chore at all. Topic progression is well laid out. I've only touched upon the first 3 chapters in any detail but, skimming through the rest, the book seems to be very very useful.
A note about one of the reviewers saying it lacks rigor: that may be true in some sense. Maybe that's why I like it to be read. But I find, that, if you're trying to get intuition about a subject (i.e., understand it in the first place), some of the details (rigor) just get in the way. This books is presented in a manner Einstein would embrace - "Make things as simple as possible but no simpler."
Also - I have this book and Stable Adaptive Systems by Narendra, which is a much harsher read. This book has bigger font, clearer presentation of each topic, and is a better overall book in my opinion.