Myst series

Just curious, are there any others past Myst 3? I have one and two (Riven is the sequel, don't think I'll ever be able to beat it without an FAQ talk about hard >_<).

I was at EBGames one time (many years ago) and saw two things that I wish I had now:  One was called Pyst, which was a version of Myst where the island was completely trashed.  The other was called Microshaft Winblows 98, and you had a virtual pet that was Billy Gates on his knees acting like a dog or something.  Good times...

I remember reading a review elsewhere that there had been many clones of the game. As of today, I cannot beat Riven without a guide. I thought I had the games # system figured out then it (literally) pulls a twnety on me.