Nihon Shinto Shi (日本神道史) (affiliate link, but only to Amazon.jp) is a history of Shinto. The first edition was published in 2010, and a new, revised and expanded edition, was published earlier this year. It is, in my opinion, the best single-volume history of Shinto on the market. It is also, unfortunately, only available in Japanese, but some of the readers of this blog might have enough ability in the language to make use of it.
It has multiple authors, all associated with Kokugakuin University, which gives it a unified approach to the topic. Most importantly, it has no time for the idea that Shinto was made up some time in the recent past. They do place the origins slightly later than I would, in the seventh century rather than the fourth, but that is due to reasonable disagreements over the point at which it becomes useful to talk about “Shinto” — the book does contain a large amount of information about the period from the fourth century to the seventh. The authors also do not believe that Shinto was ever “part of Buddhism”, and provide quite a lot of evidence to support that claim. It is indisputably true that Shinto and Buddhism were very closely interwoven for over a thousand years, but there is good evidence that people at the time thought of them as two closely interwoven traditions.
At the more recent end of history, given Kokugakuin University’s close links to the Shinto establishment, the book takes a surprisingly negative view of the Meiji government’s approach to Shinto, pointing out that it closed about half of the jinja across the country, seized all their property, and required all priests to follow the same ritual forms, regardless of their own jinja’s traditions. As I have mentioned before on this blog, I can see their point.
One of the notable features of the book is a strong reluctance to define what Shinto is. Indeed, the second chapter, dealing with the period from about 1000 to 1600, is called “The Diversification of Shinto”. It is true that some of these traditions are so different that it is not immediately clear that they should be classified as the “same religion”. My understanding is that this problem is not unique to Shinto, and that Hinduism faces the same issue. (A quick look at Wikipedia suggests that there are scholars who believe that Hinduism was invented by imperialists in the 19th century, just as there are scholars who believe the same about Shinto. Here, Shinto has the advantage that it was, at least, supposed to have been invented by Japanese imperialists.) In Shinto’s case, a lot of the common features have come from the earliest written sources, such as the Kojiki, the Nihonshoki, and the Engishiki, all of which were produced by the Imperial court, and thus emphasise the function of the Tennō. There are good reasons to believe that the Tennō may not have been central to much of Shinto practice for most of its history, and those reasons are discussed in this book, but none of the other traditions became really influential. Thus, there is a possibility that taking an overall “average” view of Shinto is actually distorting, because the common denominator is something that was not very important to many of the traditions covered.
If you can read Japanese well, I strongly recommend this book for an overview of the history of Shinto that will give you a good idea of the diversity of the tradition. If you do not, it is one of the main sources for the essays on the history of Shinto that I am currently writing for my Patreon, so you could also get its content at second hand there.