Questions about the movie

These are legitimate questions. I am not trying to disprove anyone or argue anything; they're just questions I would like answered if you feel you have the time as I don't want to watch the movie all over again:

1. Did Walter Sparrow find a publisher and have his book sold? Or did he craft this book all by himself somehow, threw it somewhere, and someone picked it up and donated it to the random books anonymous store?

2. How could the number drive someone like the doctor insane? Or do we just assume the guy was off his rocker naturally. Judging from what we saw from the movie, the doctor was the most messed up person for no particular reason.

3. Also refresh my memory on this, why was there an address in the book and why was it addressed to the doctor?

4. I couldn't find the meaning to the dog so I'd appreciate if someone could give me their two cents on him, too.

Last thought: Judging by many of the posts on this board, it appears a lot of people were affected in some way and were adding numbers together to get to 23. But, come on now, you can change almost any part of the formula or make a new formula entirely to come up with any number (even mentioned in the movie).

Hey, the number 23 came out in 2007... That's 23, er I mean 2+3... 5. Plus 2 (take out the two zeroes for some reason) plus 7... That's 5+9... That's 14. Add 9, the number of months in a year minus 3, the number of primary colors and you get...? Spooky.