I would like to learn to start investing myself. So far I have been investing in 401(K) and Roth IRA with the help of an adviser, but now I feel the need to get into it and understand how things work. And start investing in stocks, etc outside of the two retirement accounts.

The only problem is I don't really know where to begin. So I wanted to ask a few questions to the forum and take advantage of the collective wisdom. 

1. What are your favorite books (if any) on investing? Why?

2. What online trading site is best for a newbie like me to buy/sell stocks? Why?

3. What do you think are the most important things I need to keep in mind while investing in stocks?

4.  Any other advise for a beginner?