A Warning to the Hindus is a 1939 booklet by the pro-Nazi intellectual and mystic Savitri Devi. It was written in an attempt to “…make both those Hindus who are not nationalists and those Indian nationalists who do not care to call themselves Hindus into Hindu nationalists.” The author projected Hindu India as the last surviving remnant of ancient Aryan spirituality, and issued this work as a warning to what she perceived as the threat of submergence through ‘alien’, meaning non-Aryan, influences.
Foreword by “Sree” G. D. Savarkar. This book is all kinds of nasty. You can download it from, of course, a US Hindu temple’s website. The gushing Amazon review will give you an indication as to why the Hindutva movement still enjoys the patronage of the Indian diaspora.