“(M)ore than a religion or a social system; it is the core of Indian civilization.” Fernand Braudel, On History, pg.226
The subject is Hinduism.
If you plan to go to India, it’s probably a good idea to learn as much as you can about the beliefs and practices of the Hindus before you leave. Otherwise, you risk feeling as clueless and confused as I was when confronted with that country’s ubiquitous and fantastic array of Hindu gods, goddesses, mythological figures, temples, shrines, mantras, processions and festivals.