(FORTUNE Magazine) – Washington, of course, is about power. And in our story on Washington's Power 25, bureau chief Jeffrey Birnbaum delivers the authoritative taxonomy on the lobbyists who earn their living pressing members of Congress and their staffs to pass, or not pass, the laws that affect all our lives and businesses. With the help of two respected pollsters--one Republican and one Democrat--FORTUNE surveyed hundreds of Washington insiders (no journalists included) to get beyond the usual self-promotion and hype and actually quantify the clout of these powerful special interest groups. Before joining FORTUNE last January, Jeff wrote the book, literally, on lobbying. He is the author of The Lobbyists, as well as two other books on power and politics.

So, was Jeff surprised by who popped up in the Power 25? Well, yes. "I knew AARP would come out on top," he says, "but I wouldn't have expected AIPAC (the American Israel Public Affairs Committee) to be No. 2. And the Business Roundtable came out much lower than I would have thought [33]." Jeff was heartened by the range of players who dominated our rankings, taking this as further confirmation that this first annual Power 25 truly reflects political reality in the capital today.

Birnbaum also participated in another important FORTUNE Washington event recently, our CEO panel discussion on the subject of global warming and the upcoming summit in Kyoto, Japan, at which Bill Clinton and Al Gore plan to push for the adoption of new global emission standards. Check out that story in this issue, and see if you agree with Jeff that it is "the most intelligent conversation on the subject I've ever witnessed." We think you will.