Tons of Good Online Tutorials/Documents

Well, this page is really UNNECESSARY. You will see zillions of collections of famous or well-known TeX/LaTeX documents everywhere on the web, from the official TUG to numerous personal homepages. But just like a professor who fills up the office with his collectable books, I show here the documents I think worthy of reading. I might be tired of adding more items at some time in the future and stop updating this page...

Write my own tutorial some day? Oh no, you are kidding me.