I've read the Tibetan Book of the Dead and some of its modern revisions, I identified as Buddhist for years, and I lived in a Tibetan Buddhist monastery for two years. I've done these works to death (no pun intended). The basic precepts are really liberating and useful, but as you delve deeper it becomes too tied to doctrine and tradition which is not useful. To be honest, I find the belief that suffering and deprivation are the best route to enlightenment to be very old world. The era we live in now is about expansive information, creativity, freedom, and expression; we can read about all faiths now, see the common thread that weaves between them all, and walk away with that understanding. Spirit is innate and not tied to doctrine. Processing suffering is important but I see no need to attach oneself to it.
I can summarize the Book of the Dead right here in 3 modern steps:
1) You realize that the universe is outside of you.
2) You realize the universe is inside of you.
3) You realize everything is the universe, and there is no "you".
Byron Katie's works are more practical than the heady (and frankly dismal) teachings of the Book of the Dead, and there is zero koolaid. She covers impermanence, death, delusion, and all the known precepts within an easy to implement system that helps you arrive at the truth without having to study major texts. In other words, you'll understand death, delusion, impermanence, etc. without having to be directly told about them. You'll understand that every challenge is a teacher here to show you your own projections and delusions that are preventing you from living a life of love. I first recommend "Loving What Is: Four Questions That Can Change Your Life", and then "A Thousand Names For Joy". And unlike so many modern guru wannabes, she does not call herself a guru, and she has actually walked the walk through her own path of intense suffering to realize what she is now teaching.