Robb Moss previously made the documentary The Same River Twice, which expertly moved between footage shot in 1978 and in the present day as a group of friends revisited their youth and ruminated on where life had taken them. It was an absorbing, very personal account that hit on all kinds of hot button social issues -- politics, sexuality and aging among them. So I was quite interested in seeing his latest work, Secrecy, which he made in collaboration with Peter Galison.

Secrecy is somewhat less absorbing, in part because it feels more impersonal than Moss' previous work. The subject this time is U.S. government secrets. Who has them? Who needs them? Who gets to decide what's secret and what's not? Is protecting information really necessary in a free society? What if the government uses the cloak of secrecy to cover up its mistakes? How do you define national security?

Galison and Moss touch on various aspects of secrecy at the outset, and then return to their sources to develop the strands further. Journalist Barton Gellman of The Washington Post talks about traveling to Baghdad shortly after the war began and investigating the government's claim that Iraq had weapons of mass destruction. That led to many other articles questioning government assertions based on material that was classified as secret. As much as anything, Gellman seems to argue that the Bush administration's conduct has been profoundly opposed to real patriotism. In these cases, secrecy hurt.

His initial appearance is juxtaposed with a brief interview with Mike Levin, who spent 46 years with the National Security Agency. He speaks strongly against reporters, and says that the intelligent community has a word for people who reveal secrets to the enemy. He looks very pleased with himself as he waits patiently for the interviewer to finally ask him to say the word: "Traitors."

Rewinding to the post-World War II era, Patricia J. Herring remembers meeting the man who would become her husband, their short marriage and plans for the future, and his shocking death in a 1948 crash of a B-29 bomber that also took the lives of eight other men. Her husband, Robert Reynolds, was employed by an Air Force contractor. The Air Force refused to release the accident report, claiming it contained information that needed to remain secret to protect national security. The case went to the Supreme Court, which set a precedent in 1953 by ruling in favor of the Air Force and the "state secrets privilege." The case has been cited more than 600 times since then, but in recent years questions have arisen about the Air Force's culpability in the original crash and whether "state secrets" were actually involved.

And so it goes throughout the film, as the cost of secrecy is debated, covering financial terms (billions of dollars spent) and reflecting on the way that war is conducted (one expert speaks to the "pit of evil" that humans tend to draw from when faced with the horrors of war). We hear from the attorneys involving in a case brought against the U.S. in regard to the policy of secret military trials held at Guantanamo Bay Naval Station in Cuba, a case that went to the Supreme Court. The personal cost of keeping secrets is considered by former US intelligence officer Melissa Boyle Mahle -- her mother was shocked to learn some of what she had been doing, and she acknowledges that keeping major parts of your life secret from close friends tends to alienate them.

It's a hallmark of Galison and Moss' documentary that the people they assembled to speak on the subject are highly polished, articulate and intelligent: no fumbling for words, no long pauses to gather thoughts. The smooth presentations sound rehearsed, which makes the film feel somewhat dry and high-minded. On the other hand, the precision of the arguments allows for a more substantive discourse. Rather than rambling musicians trying to explain the appeal of their music, we have serious people calmly discussing why secrecy matters. I ended up feeling illuminated, if not provoked.

That's not to ignore the fact that several interview subjects become riled up, even if their passion is restrained. James B. Bruce, who worked for the CIA for nearly 24 years, speaks angrily about newspaper reports that he feels impeded the CIA's ability to track the terrorists responsible for 9/11. Melissa Boyle Mahle, mentioned above, talks disparagingly about reporters more interested in "stories" than the deadly havoc they may create. Tom Blanton, director of the National Security Archive, ruefully meditates on humanity's "pit of evil" and considers the damage that has been caused by not releasing information to the public -- he cites examples, too.

Secrecy is a very solid piece of work. What it lacks in galvanizing force it makes up for with its depth of coverage of a very important, increasingly hidden subject.