Who is your expert?

Hello!
Such an idea came to mind - now there are a lot of experts, good and others. And for many this or that person (expert) becomes almost an idol - they listen to him, they quote him, articles are written about him, etc.
So, dear community, I would like to hear who you consider to be experts and in what area?
I propose to write in the first level of comments in this format: full name (better by reference to the source), the area in which this expert positions himself.
Well, if you agree - then we add this comment, we do not agree ... Just let us in a civilized way - if you put a minus - write down why. OK?

I think the information will be useful to many.

Zy The expert is actually not the right definition, but since many experts call themselves this word, then so be it.
')
UPD: write to one expert in one comment, because as noted below, it is impossible to vote for one without affecting the other.