Best books on Shinto. A list: 1º - "Shinto, the Way of the Gods", by W. George Aston.

 ASTON, William George.  SHINTO (The Way of the Gods). London, Longmans, Green, and Co. 1905. In-4ª II-390 p. 

A very detailled account of the formation, characteristics and history of Shinto, made by William George Aston (1841-1911), a remarkable author of grammars and history of Japanese literature as well as translator of one of the two mythical and foundational books of the story of Japan, the Nihongi (compilation from the year 720). He is considered to be one the best japanologists of XIX century, having lived 25 years as diplomat and scholar in Japan and Korea.                                             
                                                               
It has forteen chapters and with 16 illustrations and very good contextualizations, with examples not of only from Japan, but also from others traditions. In the preface the author points to his special indebtedness to Edward B. Tylor's, Primitive Culture and James George Frazer's, Golden Bough.
                                                                

In the firsts chapters he points the roots of Shinto, as for example Korean ones (not specifying the Shamanism), and the materials for the study, and shows how personification of natural forces (like the Sun Godess, Amaterasu omikami) and deification of human beings (like, for example, Temmangu, the god of learning and calligraphy, ) has originated the multitude of Kamis and how the polytheistic character of Shinto is mitigated, as there is the general consensus that the important is not the name of the Kami but de fact that a Kami, god, spirit or deity, is present there, giving beautiful examples like a poem written in the famous and so inspiring (as I experienced by myself)  Ise shrine:  «What is that dwelleth here I know not, yet my heart is filled with  gratitude and the tears tricke down».

Surely I would not endorse fully this Aston's positivist and animist view as, for example, in my vision Amaterasu omikami is a Feminine Divine Face or Being or, we may say, a Feminine Face of the Solar Logos...
Very well developed are the chapters on the Pantheon of Nature and Man Deities (Kamis), around eighty pages, where he describes many Kamis and shows the roots from which they derivated the names, and describes their characteristics and also the Shintai (the body or token representative of God) of them, sometimes carried in procession in the Mikoshi, or carriage of God. Also importants are the chapters on the Priesthood, the Worship (with its instruments, simbology and functions), Morals, Law an Purity, the Cerimonial (with many examples from the Matsuris or festivals), the Magic, Divination (transcribing some famous Oracles) and Inspiration, with very curious pratices, sometimes a bit ruthless.
Last chapter speaks about the rise of Budhism, the formation of new sects, like Ryobu Shinto, Yui-Itsu Shinto, Deguchi, Suwig, seeing them, as a decay of Shinto. Then refers the revival of Pure Shinto in the XVIII, with Kada, Mabuchi and specially the great Motorii Norinaga (1730-1801) and his disciple Hirata Atsutane (1776-1843) who have made commentaries in the old books with interesting new proposals and syntesis, and become the basis of the restoration of the Mikado. The last sects mentioned are Shingaku, and two founded by peasant women, very emotional ones, with faith healing, Aston comparing them even to the Salvation Army: they are Tenrikyo and the Remmonkyo, about this one saying: «The shintai, or material representative of the Myoho, is a slip of paper bearing the words Ji no Myoho, Wonderful Law of things)», being used in chants and as a charm.
He didn't foresee that many new sects would develop, some with deep spirituality, or better spiritual understandings and pratices, and he seems to have done another incorrect prevision, when writes that beyond Budhism «another and still more formidable rival has appeared, to whose progress, daily increasing in momentum, what limit shall be prescribed?» Without mentioning explicitly, he is speaking surely of Christianity...
And he finishes with another a mistake, saying that «As a national religion Shinto is almost extinct», as we can see so alive in XXI century, even after USA bombs, opression and influences. And then, follows and finishes better, writing: «But it will long continue to survive in folk-lore and custom, and in that lively sensibility to the divine in its simpler and more material aspects which caracterizes the people of Japan», this sensibility so well felt and described with insuperable quality by Wenceslau de Moraes (1854-1929), almost at that time.

It has a index with eleven pages, in small letter, very useful.

It is also important the fact that George Aston was using thousands of old books, and at the end of his life he and Ernest M. Satow gave 10.000 books to the library of Cambridge University. At least these ones were not destroyed by USA bombardments in II great war.
He uses quotations from the old mythic texts but also from the classical Shinto philosophers, as Motorii and Hirata, and others westerners field researchers on Shinto or japanologists, like Ernest Satow, Weston, Chamberlain, etc.
He gives many japanese synonyms words for the main aspects of Shinto, distinguishing them very well, as he was a specialist of Japanase language, as for example, Shrine: Miya, Araka, Yashiro, himorogi, Jinja, having all them the main meaning of a house for the God.
It has many pratical aspects relating to purification and spiritualization, the use of the salt, the gohei, and giving many examples of noritos or prayers, highligthning the sober style of mentioning the deities, compared to other religions, where there is only «a few adjectival prefixes to the names of the Gods, such as oho, great, take, brave, taka, high, kaya, swift, toyo, rich, iku, live, yori, good..»

Surely one very good book, even with not so perfect conclusions,  to introduce people to Shinto, with deep knowledge and sensibility.