Edward Jay Epstein made headlines Friday with a big interview with Dominique Strauss-Kahn, drawn from his ebook original Three Days in May: Sex, Surveillance, and DSK, just out from Melville House. It’s reviewed in today’s New York Times, and an excerpt, the opening chapter of the book, appears below.

There was a time not long ago, indeed up until the first decade of the twenty-first century, when surveillance often required a physical presence. Images of members of a surveillance team breaking into a home to plant a microphone, sitting in a parked van with earphones and cameras, climbing a telephone pole to install a tap, and following a man to a meeting place were burnished in the popular imagination by movies such as The Conversation, Tinker, Tailor, Soldier, Spy, and The Lives of Others, each of which had a basis in reality. Now, however, with the proliferation of smart phones, credit cards, EZ Passes, GPS trackers, e-mails, text messages, and closed-circuit television (CCTV) cameras, such surveillance can be done from a remote location.

When individuals use these ubiquitous devices, or are exposed to them, to make a call, go on the Internet, drive their cars through a toll plaza, pay a bill electronically, visit a social network,use Twitter, or share a photo, they leave a digital trail that can be reconstructed. Camera-equipped phones that locate the user via a rapid GPS signal, which were rare at the time of the attack on the World Trade Center in 2001, are now used by a large part of the population to phone, text, e-mail, store voice mail, conduct Internet searches, pay bills, and organize appointment calendars. These data are routed through cyberspace via a ganglia of Internet service providers, or ISPs, by global telecommunications companies.

Once a security service acquires the ability to hack into the ganglia, it only needs to determine the phone number of a target to follow his or her every move, past and present, in cyberspace. Nor is it an insurmountable challenge for even a second-rate intelligence service, if it is well funded, to obtain this capacity. After Muammar el-Qaddafi’s regime fell in 2011, documents found in Libyan intelligence by the Wall Street Journal revealed that Amesys, a subsidiary of the French company Bull SA, had supplied Libyan intelligence with its EAGLE Interception system, which allowed Libyan intelligence to gain access through ISPs to the smart phones of a vast number of suspected dissidents and then, through special filtering software, intercept their e-mails, online chats, and Facebook messages through what the company called “massive interception.” If such products are commercially available, it is not difficult to imagine what a first-class intelligence service can achieve in terms of remote surveillance.

A former top executive of the National Security Agency said to me in 2011, “If just twenty years ago a book described a world in which every citizen voluntarily carried around his own bug so Big Brother could listen to his conversation, it would be deemed science fiction, but now it is no longer fiction.” He explained that since a smart phone contains all the elements necessary for surveillance, including a power supply, a microphone, GPS, and a continuous transmitter, “any security service can send it software codes that will turn it into a bug that monitors conversation even when the user believes it is turned off.”

A sophisticated target can, of course, take counter-measures, such as removing the phone’s battery when having a sensitive conversation. In this game, even such a move can be defeated by planting a hidden capacitor in the phone, which will act as a spare battery, although this requires physical control of the phone itself.

Similarly, if a computer is connected to a network, a security service can remotely embed a program that will allow it to monitor all the keystrokes a target makes on it. And with a facial-recognition program, a security service can follow a person’s movements on networked CCTV cameras, which are already ubiquitous in some cities, such as London. As a result, much of what a person does, whether he realizes it or not, is time-stamped by a digital camera or cell phone.

On May 14, 2011, when Dominique Strauss-Kahn, better known by his initials DSK, had his now-infamous encounter with a maid at the Sofitel in New York, much of what occurred before and after was captured by elements of this new surveillance regime, including CCTV cameras, cell phone ISPs, credit-card charges, radio police logs, and the hotel’s electronic key-swipe records. After DSK was arrested on charges of sexual assault, the Manhattan district attorney’s office subpoenaed that material. In August, however, the district attorney came to the conclusion that the only witness in the case, the maid, could not be believed beyond a reasonable doubt, and he moved on August 22, 2011 to drop the case.  After the charges were dismissed, I obtained a significant part of this evidence, from sources that prefer to remain anonymous, for an article I was writing for the New York Review of Books. After the article, “What Really Happened to Strauss-Kahn,” was published in November 2011, many more of the court-protected documents became available to me. This time-stamped material, much of which is included in this book, allowed me to reconstruct the reality behind the mystery in a way that I could not have done otherwise.