Today, I learned about Mystcraft. I had been wondering, and even posted a question on here, why I hadn't been finding those Mystcraft temples with all the bookcases and the lecterns and the hidden chest and the all-important pages. I was Mystified.
It turns out, the answer seems to be that Mystcraft does not add worldgen to the overworld! What you're supposed to do, I think, is to make a few random ages by placing a "link panel" into the book binder, and you make a random age. In those random age, THAT is where Mystcraft adds its Temple worldgen. You explore the random ages that don't have bad effects, and you collect pages in them, and then you assemble your own ages when you get the right pages. I feel kinda stupid for not realizing this, but I'm also excited because this opened up a whole new dimension (literally) on my world!