Answer:
Adored by few, feared and hated by many. Mistress of the entire universal reason, master in the art of numbers. Some may have solved many of my mysteries, but there are still many of them to find. What am I?
I run through hills. I veer around mountains. I leap over rivers. And crawl through the forests. Step out your door to find me.
I have no voice but I can teach you all there is to know. I have spines and hinges but I am not a door. Once I’ve told you all I cannot tell you more.
I am an activity dogs are very good at when a ball is thrown.
If you drop me I'm sure to crack. But give me a smile and I'll always smile back.
The answer I give is yes, but what I mean is no. What was the question?