I attended a few of Prem Baba's seasons at his ashram in Brazil and the Sachcha Dham ashram in India. I learned a lot from his satsangs/discourses.
I think this book is difficult to fully understand if you haven't already familiarized yourself with the "lingo" of spiritual terms and ideas circulated in the Prem Baba sangha during the time of the publication of this book. That's not to say it's a you-had-to-be-there situation, since the ideas he talks about in the book are supposed to be spiritually intrinsic, so any "seeker of the truth" should be able to discover the meaning within while reading this book.
That said, it does help if you were there. If you weren't, you could just listen to a number of his satsang recordings from anywhere before 2014 and you'll be able to acquire that "lingo" pretty quickly.