A brief but solid introduction to Pentecostalism. The history section was good, and I found the section on the prominence of apocalyptic beliefs in Pentecostalism interesting. It was especially interesting in the last chapter (on surveys) when Kay mentions the Bertelsmann Stiftung survey's findings on Nigeria and the overlap on Nigeria's Muslim and Christian (Kay speculates prominently Pentecostal) beliefs in apocalypticism and spiritual warfare, as I was just listening to a lecture earlier today about the prominence of apocalyptic beliefs in early Islam.
Another thing I liked was Kay engaging with ideas from two other books in the Oxford VSI series, albeit briefly. I also found it interesting Kay's overview of sociological perspectives on the fast growth of Pentecostalism in the US and how that related to the experiential dimension of religion so prominent in Pentecostalism. Before this I read Stephen Prothero's book on religious literacy and was reminded on his situating the rise of experiential Christianity with the decline of religious education (and by extension a decline in knowledge of doctrine and the like). Speaking of Prothero's book, this is now the second book in a row I've read that mentions Aimee Semple McPherson. She sounds like she was an interesting person, so I look forward to reading more about her life.
As for problems, I would have liked more of an in depth description on what Kay refers to as "Neo-Pentecostals" and their development. Are those the same as Neo-Charismatics? And I would have liked a more in depth look at the apostolic networks discussed at the end of chapter 5. These issues I have are expected though, given that Pentecostalism is clearly diverse and this is a "very short introduction". Also, Kay's own Pentecostal views become apparent sometimes, like his mention on page 114 on the belief in luck in Asian cultures as "reckless", which really wasn't necessary.
A decent introduction, and I'll certainly read more on the subject. I'm particularly looking forward to reading a more in depth account of Pentecostalism in the US, as well as the early development of the Charismatic movement.