(source: Ice -T's Introduction for Iceberg Slim's novel Pimp, The story of my life)

The sentence itself:

"We fond the books, and we started passing them around to each other. We felt like we were part of this cult-like underground, cause they let us in on something real -Iceberg's words."

Context:
Ice -T tells how he and his friends discovered Iceberg's books when they were children.

I know every world in the sentence but I could hardly mine out the real meaning(s) of it. A most valuable help for me would be dissolving this complex sentence to simple the simple short ones it states or implies. here's how I would do it:

1. Slim's books made Ice-T and his friends feel like they were part of some cool subculture.

2. This was because Slim described a world in his stories that seemed very real to them, they actually recognized their own circumstances and experiences in those books.

3. Iceberg's books made them reflective upon their life and they started to consider their conditions as something to be proud about

The most difficult parts of the sentence for me are the 'let us in on' expression and the very end of it ' -Iceberg's words' I would e glad to know exactly what does it refer to