The first chapters were very useful to me, as they helped me to find purpose and focus in my bullet journal practice again. However, if you're only interested in learning the method and techniques of bujo you could more easily get that info from the creator's youtube channel or even the website. Chapters 3 until the end take a strong detour into self-help territory which I was skeptic at best, and positively cringed out when a Thomas Edison quote was mentioned to further a point. I don't like the focus it takes on productivity and how Ryder's philosophy adapts management philosophies and techniques to day-to-day life, but I do acknowledge that this could be helpful for some people.
That said, the book wasn't for me, but the system sure is: going for my 8th bullet journal this year!