Thirty books, some the kind you could pick up in your local library, others that are carefully hidden away from the general public for good reasons.
30 books to be found within a steampunk setting. Manuals, tomes, and blueprints galore!
The religion believes in reincarnation, but that you will be reborn in the past. People of today are those re-born of tomorrow, with some discarded as trash. The most pure will be eventually reborn in the mythical paradise-like past, where people lived for hundreds, or maybe even thousands of years.
This goes nicely with beliefs into foresight (you know a little about the future because you have been there), but also to many complaints of how things are going always from bad to worse.