I have two of her books and consider them as near textbooks on the teachers and teachings of those who have made spirit quests and those who are embarking upon their own. She's totally non-judgemental and presents everything in a reverential & understandable way, that's not over-the-top. This one lets us join her as she is questioning everything and not at ease with her answers, thusfar; but, not agnostic, just wanting "truth"..and willing to go all out to find her own truth. She's been involved in Hollywood productions and I'n surprised that she's not made her own movie. I suspect she's not past the first few chapters, in living her life's story out, yet. This might be considered the "introduction" to it.
Next, get her wonderful "textbook"..Spirituality for Dummies. If you're at all "into" this sort of spiritual examination, it's essential.