These vacuum devices stood guard during the Cold war, advanced particle physics, treated cancer patients, and made the Beatles sound better

IN AN AGE PROPPED UP BY quintillions of solid-state devices, should you even care about vacuum tubes? You definitely should! For richness, drama, and sheer brilliance, few technological timelines can match the 116-year (and counting) history of the vacuum tube. To prove it, I've assembled a list of vacuum devices that over the past 60 or 70 years inarguably changed the world. • And just for good measure, you'll also find here a few tubes that are too unique, cool, or weird to languish in obscurity. • Of course, anytime anyone offers up a list of anything—the comfiest trail-running shoes, the most authentic Italian restaurants in Cleveland, movies that are better than the book they're based on—someone else is bound to weigh in and either object or amplify. So, to state the obvious: This is my list of vacuum tubes. But I'd love to read yours. Feel free to add it in the comments section of the online version of this article (where you will find two more tubes not included in print). • My list isn't meant to be comprehensive. Here you'll find no gas-filled glassware like Nixie tubes or thyratrons, no “uber high” pulsed-power microwave devices, no cathode-ray display tubes. I intentionally left out well-known tubes, such as satellite traveling-wave tubes and microwave-oven magnetrons. And I've pretty much stuck with radio-frequency tubes, so I'm ignoring the vast panoply of audio-frequency tubes—with one notable exception. • But even within the parameters I've chosen, there are so many amazing devices that it was rather hard to pick just nine of them. So here's my take, in no particular order, on some tubes that made a difference.