... you have to understand the nature of the system they have put in place, why they have done it, and how they maintain it.
Carroll Quigley explained to the world the what and why. He should know because he was invited by "them" to go over their historical records and became their official historian.
Cecil Rhodes was instrumental in developing the system that was later put in place which, believe it or not, is based on the old Illuminati structure (which was discovered in Germany in the 18th Century), and is why a lot of people still refer to "them" as Illuminati. It's not that that particular organization lasted 200+ years, it's just that the same structure was put in place and for largely the same reason.
You also have to understand that many of the people involved are "useful idiots" in that they are not in the INNER circle, but generally think it is great to be near sources of financial power because it gives them a cushy life, financially, as well as the opportunity to mingle with well-known people.
We can never know who ALL of "they" are because the very nature of it is to be secret. If we had subpoena power, we could learn a lot. Since we don't we have to learn from those who have tried to let us know, and put two and two together.
This speech by G. Edward Griffin is the best there is at describing the what and why, and a little glimpse of the who:
This interview of John Perkins is the best there is at describing how the power stays in power (ultimately, due to their willingness to commit murder):
Quotes by David Rockefeller:
"We are grateful to the Washington Post, The New York Times, Time Magazine and other great publications whose directors have attended our meetings and respected their promises of discretion for almost forty years. It would have been impossible for us to develop our plan for the world if we had been subjected to the lights of publicity during those years. But, the world is now more sophisticated and prepared to march towards a world government. The supranational sovereignty of an intellectual elite and world bankers is surely preferable to the national auto-determination practiced in past centuries." -- David Rockefeller in an address to a Trilateral Commission meeting in June of 1991
"For more than a century, ideological extremists at either end of the political spectrum have seized upon well-publicized incidents to attack the Rockefeller family for the inordinate influence they claim we wield over American political and economic institutions. Some even believe we are part of a secret cabal working against the best interests of the United States, characterizing my family and me as 'internationalists' and of conspiring with others around the world to build a more integrated global political and economic structure - one world, if you will. If that's the charge, I stand guilty, and I am proud of it." -- David Rockefeller, his autobiography, "Memoirs"
David Rockefeller is either THE kingpin or one of them. Any person or organization that he touches in any way is suspect. And anyone who he is associated with who also is associated with multiple such organizations is also suspect. Many people, however as I said above, are "useful idiots." The people who actually push the agenda probably number in the thousands. The people who really understand the full scope of the structure and who is who probably number in the hundreds, if that. And the true kingpins on the real inside are probably just a handful or two.