I first learned about the Curta from this January 2004 article in Scientific American, by Cliff Stoll. Unfortunately, the article is not available for free. But you can purchase a PDF of the whole Jan ...

This compact cylindrical handheld calculating machine has black metal sides and a plastic top and operating handle. Eight slots along the side of the cylinder hold levers that are pulled down to set ...

I worked with a guy who found one of these at an estate sale in a box of used camera lenses. He didn't know what it was but it looked expensive and said "Made in Germany" so he figured it was worth ...