Look at it another way: imagine a camera with a certain shutter speed taking a picture of a cat. If the cat is asleep in the same place, centre frame, then the

Look at it another way: imagine a camera with a certain shutter speed taking a picture of a cat. If the cat is asleep in the same place, centre frame, then the picture will almost certainly be of the cat. Should the cat wish to not be photographed then the cat could go into one of those poses used when hunting prey - ears flattened, tail down etc. The cat will present a smaller cross-sectional area and not be seen as easily. Who knows, could be mistaken for 'a bumblebee'. This is 'cat stealth' - see 'ninja cat'. Alternatively, the cat could just leap past the camera at phenomenal speed. Most of the exposure will be of the background however there could be some light blurring where the cat has leapt across the frame of the picture. On initial inspection a cat would not be seen, just some shadowy/tabby artefacts. If the camera was one of those early CMOS sensor things and the light levels were low then the shadowy/tabby artefacts might not make it past the background noise that came with those sensors. In this way a sufficiently fast cat could hide in plain sight from a camera that had an early CMOS sensor. To make extra sure that the cat was 'invisible' the cat could be instructed to flatten its ears as it rushed through the frame. Clearly I wasn't around in the late 1950's, however, I think my analogy describes how 'early stealth' worked by just being very quick. You should get the concept now. In the military/intel or even normal companies knowledge and information isn't globally shared so maybe the author didn't know some aspects of the project or those details were not pertinent to what they were doing. I should have cited sources but cat analogies are more fun.