<human>: Can you summarize the given text in a few sentences?

I've been running for a year. I run about 20-25 miles a week and my average mile is 8:30. My longest run is 5.5 miles. I stretch, eat well, and do cross training and work out before/after I run. I know that marathon training is Serious Business and I think I'm at a point where I need real advice, instead of winging it.

I'm constantly learning new things and forming new questions: 
"There's a lottery? What % of a marathon is determined by lottery?" 
"TOENAILS FALL OFF?" 
"Why are people wearing what looks like tights, but only up to their knees? Do I need those?"

So, runnit, I'm looking for solid book/website advice or recommendations. I like to have as much information as possible before I undertake a project. I'm also very keen on your tips and advice / _things you wish someone had told you before you started training_ .

I know someone posted about marathon training last week, but that was mostly about food. I'm after sources of information/guides.
<bot>: Running 20ish miles a week. Looking for good sources on marathon training so I don't hurt myself/can accomplish my goals. Also, please tell me things you wish you had known before you started training.