SECRECY IN THE WAR on terror has proved rich ground for artists. Many have exploited the theme of surveillance, tracing data trails and security cameras, alerting us to our own complicity in watching and being watched. But equally attractive has been the fact of the secrets: the blanks, the unknowns, the redactions.

“Negative evidence is when the very act of redaction is evidence in itself,” says the architect Eyal Weizman, “when the absence of evidence operates as evidence in its own right.”

The artist Jenny Holzer began making “redaction paintings” in 2004, working with military and intelligence documents that included the sanitized handprints of soldiers accused of war crimes in Iraq. Trevor Paglen, an artist and geographer, is obsessed with the “blank spots on the map” created by government secrecy, which he documents through photos of classified U.S. military installations taken from a distance with a telescope, or of the anonymous corporate architecture around Washington, D.C., that houses U.S. intelligence agencies. The work of Mishka Henner highlights the bright polygons that the Dutch government uses to block secret sites on Google Maps.

Redaction is also a theme of Laura Poitras’ show currently on view at the Whitney Museum in New York City (Poitras is a founding editor of The Intercept). In one installation, “Disposition Matrix,” visitors proceed through a space that has been almost entirely redacted: a blackened corridor with illuminated slots that let visitors look at documents and images. The source material refers to a range of government programs; the slots don’t build a narrative, and the signage accompanying them gives visitors only the briefest context. Some of the slots are high up or down near the floor, making them awkward even to look into.

This experience is not untrue to the process of investigating the dark world, where clues appear in fragmented form, context is missing, and there’s always a possibility that there’s more you don’t know. In presenting the surface of these programs — through architecture or bureaucratic paper trails — these artists push us to wonder what’s beneath them, while also experiencing the bewildering, maddening fact of their invisibility.

A new book, Negative Publicity: Artefacts of Extraordinary Rendition, joins this fixation on the black mark, but with more of an eye to elucidation. A collaboration between the photographer Edmund Clark, who has produced work about Guantánamo and Afghanistan, and Crofton Black, a researcher who has investigated counterterrorism for human rights groups and journalists, the book presents primary source documents about the CIA’s rendition and detention program, along with photos of the program’s physical infrastructure: airports, front companies, hotels, and prison sites.

Between 2002 and 2008, the CIA bundled dozens of people to black sites around the world, interrogating and in some instances torturing them. In Negative Publicity, which is published by Aperture and Magnum Foundation, Weizman notes in the afterword, “What we see is not torture, or detention; we see the attempt to mask these procedures.” After all, “every secret operation exists in the world and has to interact with the world around it. Petrol is required, food, clothing.”

At first navigation, it can be overwhelming to go through the heavy, spiral-bound book of color photographs interspersed with grainy reproductions of documents. But if you sit down and read it in sequence, the book has actually broken the mysteries of the rendition program into intelligible stories.

Black opens each section with an essay on a particular episode in the rendition program. One of the world’s experts on the program, Black has plumbed every possible source material, from Italian criminal proceedings against the rendition team who abducted the Egyptian cleric Abu Omar from the streets of Rome, to a lawsuit between aviation subcontractors who operated the rendition flights.