I also don't know what it is, but, the feeling of it all being a scam is also my first thought whenever I hear about it... However, I've once seen a documentary

I also don't know what it is, but, the feeling of it all being a scam is also my first thought whenever I hear about it... However, I've once seen a documentary about some Buddhist monks who truly "did it" and I absolutely believe that for them, or rather, if done properly, it can truly be a really life changing experience... But I think that no amount of book reading or self practice will help you reach it... So yeah... Mixed feelings for me until I'd be able to do it in the mountains with monks who've been at it for decades now