At first glance, you couldn't choose a less visual film subject than secrecy. It is by definition the topic you are forbidden to see, with sources who, by profession and inclination, won't tell you anything. And yet secrecy has a grip on us, on our political being, on our imaginary lives, on our sense of privacy. This was where we began our film, convinced that it was a central topic of our time, one that we all related to—and yet utterly baffled about how we were going to bring it to life.

We began filming in a rather traditional way—in fact, the first interview, one we didn't end up using, was outside on a brilliant fall day on the Chesapeake coast, a retired national security official who once bore responsibility for guarding the most dangerous knowledge—of nuclear weapons. But there was something profoundly wrong about trying to enter into this world with birds chirping and the water lapping at the shore. After a lot of thinking and experimenting, we realized that we needed a more hermetic environment, the controlled, highly focused lighting of a sound stage. No books or shelves—or birds or boats—in the background, but instead the most artificial space we could construct. We set up a rear-projection screen, with the background scene alluding sometimes directly, sometimes metaphorically, to the world of the person being interviewed. This sealed-off volume became the reference point of the film, intimate and a little disturbing, disconnected from the outside and yet all the while wandering through questions of agents and betrayals, wars and information, power and the impact of secrecy on those caught up in it.

The intense, intimate setting for the interview did set the tone we were after, and we decided to work with an editor and a composer from the get-go. Instead of collecting all the materials first—and then editing—we decided to make the film grow out as it needed to rather than push our interviews and materials into a pre-determined mold. So we began editing immediately after our first sound-stage interview. Chyld King, our terrific editor, came on board then. Our first edited piece was a few minutes long. Alongside our bringing on board an editor, we started working with composer John Kusiak, thinking together about how we wanted the score to interact with the film: where individual instruments needed to stand out, where we wanted more of a progression.

Secrecy resonates with everyone. But we were not at all sure that in interviewing professionals that they would think—or want to discuss—how layered the political, technical, or military secrecy was on personal associations. On this score, we needn't have worried—just about everyone, whatever his or her position or politics, had rather strong views about the ways that sexuality, secrecy, and power thread inevitably around one another in our imagination. Knowing that our interview footage would be so highly confined, we wanted a way to let this other, more personal dimension of secrecy crack through the more deliberate, intended meanings. It was thinking about this problem that led us to animation—not purely as illustrative of what we were not allowed to see, but as invoking a more associative kind of imagery. Animation—mostly of an almost wood-block expressionist kind led by Ruth Lingford—served as this underground lava stream, bursting out, intermittently, from the first moments of the film all the way through to the end.

But who to interview? From the beginning, we aimed to show a world of secrecy as seen by those in it, not by pundits celebrating or castigating from their perches. Nor did we want famous former heads of agencies or high-ranking politicians who had already spoken so frequently on issues of public policy that they were likely to quote themselves—or return to justify actions they had taken. Instead, we wanted to get a sense of how more usual people moved in the shadow world—agents and analysts, for example. One of the former agents served in many postings across the Middle East, Africa, and Central Asia, including years as CIA Station Chief in Jerusalem. Our other Agency interlocutor worked both in the Intelligence and Operations Directorates; inter alia, he helped run a group on "Foreign Denial and Deception" (a fabulous title that means denying information to other intelligence services and deceiving them). He also takes very hard-line stance on press leaks. Finally, from the National Security Agency, we found the NSA's long-time head of information security, a guardian of the secrets of the most secretive of government agencies—they make the CIA look open.

On the other side, equally passionate, were soldiers in the secrecy wars who were just as persuaded that the future of democracy depended on arresting the helter-skelter increase in classified information. These include the head of the Government Secrecy Project at the Federation of American Scientists, a group committed to tracking, analyzing, and opposing the steady increase of classified information. Joining him as a secrecy critic is the director of the National Security Archive at George Washington University. Using the Freedom of Information Act, this NSA (not the infinitely larger government three-letter agency) has published declassified documentation of a vast range of events—from the Cuban Missile Crisis of the early 1960s through very contemporary events. These documents recast our understanding of turning points in recent history.

People often ask us if we had trouble getting access. There were many very difficult parts of making Secrecy. As it turned out, access was, perhaps surprisingly, not one of them. Our goal from the start was not to expose this or that technical detail—we were not out to publicize how high, fast, or far a particular fighter jet could fly. Instead, what interested us was the system itself: How did classification function, what effect did it have on those inside and outside of it, what issues did it raise for security, for press freedom, for separation of powers, for deliberative democracy itself?

To make visible this rather abstract set of concerns, we soon realized that we'd need specifics, and we wanted the most forceful case our subjects could mount, not some casual remark or the embarrassed silence and turned faces that accompany ambush questions. So over and again we asked the people with whom we spoke to take their best shot, to choose the instances that best illustrated their most central and compelling arguments. Then we dug in. For the National Security Agency that meant taking us back to Beirut, where a 1983 disclosure about NSA monitoring meant the loss of a crucial electronic source, and the Marine barrack attack. For a Washington Post special projects reporter who appears in the film, that meant something very different: the absolute impossibility of the public deciding issues central to democratic deliberation if one didn't know. From the reporter's perspective, if the press obediently avoided all secret topics, that would have meant the public would not have the very basic elements of the “war on terror”: that the hunt for weapons of mass destruction was an absolute bust, that the United States was engaged in “extraordinary rendition,” that Bin Laden had escaped from Tora Bora. Yes, he says, these were classified secret, but if the papers reported only what the official line was, the American people would not have understood the basic elements of the “war on terror” as it was actually being conducted.

Bit by bit, we began to find ways to get at this epoch struggle over secrecy—what the stakes were, how to make the secrecy wars visible, how to shuttle between the political and the personal. But we knew that the film couldn't work as we wanted it to if it did not find a way to get at how the rubber met the road—how these positions, passionately held as they were, played out in the broader world.

So we chose two remarkable and hugely influential Supreme Court cases—and followed what they meant for the structure of secrecy. One case launched secrecy in early years of the Cold War; the other is urgently contemporary, still being fought, and it shapes and reshapes boundaries between the president, the law, and secrecy. We ended up wending both of these cases through the film—they take battles over secrecy and give them a human, personal dimension.

Throughout the long process of making this film, we've intentionally not proceeded as if the issue of national security secrecy could be "solved" with an easy set of steps. We see the issues of secrecy as tough, among the hardest we face as we, and not just in the United States, struggle to bolster democracy in a time of great fear.