I found this book frustrating. Even though the authors claim "interspirituality" -- with no further modifiers -- they are squarely centered in monotheistic theology and worldview. So as a polytheist reader I found that most of it did not align with my own theology, worldview and practices. They also spend a lot of time explaining and justifying interspirituality and their form of monasticism, and I didn't need to be convinced. I almost abandoned it, but instead I skimmed it for useful nuggets because mature writing about monasticism which is not centered in a specific tradition is rare. Even though though I'm not their target audience I have a great deal of respect for their work.

If I were a spiritual-but-not-religious or "interfaith" person with a monotheistic worldview, I would give this book five stars. It's excellent. But as a polytheist, from a standpoint of personal enjoyment and usefulness, I'd give it three.