This is a good introduction video on the puzzle https://videosift.com/video/Cicada-3301-An-Internet-Mystery
The current Puzzle 3 has not been solved. By seeing all the fantastic talent here on these forums and the Discord channels, I think Puzzle 3 may be solved! -)
TQQdles™
Liber Primus is painstakingly hard, with only 17 of the 57 pages solved. It will not easily be solved any time soon. It has been several years now and most lost interest in attempting to solve it.
I do occasionally work on it and have at times been actively participating back in the days. Not active enough to fully keep up though. The mystery surrounding it just intrigues me and most of the puzzles were fun … until Liber Primus that is 
It certainly increased my interest in Steganography as well as Cryptography. Would love to see it fully solved at some point.
For those interested, I would suggest to check the below wiki, as it covers pretty much all, and has links to tools and whatever needed, as well as original sources. There is still a small active community working on it, check out the freenode IRC. I mostly work on my own though, just for fun, whenever I feel like it.
Note: Beware of false paths, there are many. Avoid ending up in a deep dark hole, chasing rabbits!