“What is the ultimate answer to life the universe and everything?”

I had no clue, nor did my wife that 42 was the answer. Yet 42 is one of her favorite numbers.

I did not read the book you mentioned, but as for changing the world, really all we can do is change the little part we live in, and try to make a difference there. If everyone changed/fixed something in their backyard we would have a better place. But humans being humans, it matters not how much you clean your front lawn, some asshole's dog is going to come along eventually and crap on it.

One really important question is how you divide the difference between right and wrong.

The difference between right and wrong is in the eye of the beholder. If it is wrong to murder someone, then killing a murderer is also wrong. So in this case two wrongs do make a right.