Did this take me way to long to finish? Yes. Do I think that the Zaleski's love a sentence too long for its own good? Yes. Did I fall asleep while reading it three different times? Yes.
Was this also a five star book, going by literally any metric of quality other than "zippy"? Also yes. Because if you are like me and you like to know everything about everything and you don't know where your personality ends and the fun facts begin, this is a great book. It takes the practice of prayer, smashes it, and then examines it on the molecular level. It looks at its many components, and the forms that stay consistent across differing religions, time periods, and people groups. It looks at the stages of prayer, the categories of people who pray, the types of prayer, and types of expression. There's a reason a full tenth of the book is citations, because it talks about everything from the Mithratic mysteries to Vermeer to the efficacy of Native prayer-dances to Supreme Court cases to the practices of Sri Ramakrishna.
My brain is now very full and very stressed. Please pray for it.