You see, cats are sly and unpredictable. They can slip unnoticed from place to place, watching, listening, wryly judging, surveilling.

So, why wouldn't the Central Intelligence Agency stick a microphone in a cat's ear and embed a radio transmitter in her body? Oh, but they would! In an excerpt from her new book published at Popular Science, Emily Anthes describes the mid-century attempt to create a feline operative, Operation Acoustic Kitty. (See the redacted CIA memorandum describing the activity, too.)

In an hour-long procedure, a veterinary surgeon transformed the furry feline into an elite spy, implanting a microphone in her ear canal and a small radio transmitter at the base of her skull, and weaving a thin wire antenna into her long gray-and-white fur. This was Operation Acoustic Kitty, a top-secret plan to turn a cat into a living, walking surveillance machine. The leaders of the project hoped that by training the feline to go sit near foreign officials, they could eavesdrop on private conversations. The problem was that cats are not especially trainable--they don't have the same deep-seated desire to please a human master that dogs do--and the agency's robo-cat didn't seem terribly interested in national security. For its first official test, CIA staffers drove Acoustic Kitty to the park and tasked it with capturing the conversation of two men sitting on a bench. Instead, the cat wandered into the street, where it was promptly squashed by a taxi.

The project made even hardened operatives squeamish. In 2001, a former CIA agent gave The Telegraph newspaper some more details about the animal. "They slit the cat open, put batteries in him, wired him up. The tail was used as an antenna. They made a monstrosity," he said.

For Anthes, though, Acoustic Kitty is only one in a long-line of military cyborg creations, one that's been unrestrained by moral considerations. "We can make tiny flying cyborgs--and a whole lot more," she writes. "Engineers, geneticists, and neuroscientists are controlling animal minds in different ways and for different reasons, and their tools and techniques are becoming cheaper and easier for even us nonexperts to use. Before long, we may all be able to hijack animal bodies. The only question is whether we'll want to."