I can see him in his glass-fronted Cambridge office from the foosball table in the light-filled central atrium. He’s standing there talking to a visitor and seems to be finishing up. This entire side of the third floor in MIT’s new Media Lab building is partitioned with glass, and professor Hugh Herr and his colleagues and whatever madness they’re up to in their offices and the open, gadget-filled, lower-floor lab are on display. Several people, myself included, are peering down, hoping to see a bit of magic.

Months ago, when I e-mailed Herr to propose writing an article about him, I told him about my rare bone cancer and resulting partial paralysis below the waist as a way to explain my interest in his work. Though I didn’t tell him this, I also harbored a secret wish that he could help me. People write to Herr, a 52-year-old engineer and biophysicist, daily about his inspiring example. They’ve heard him promise an end to disability. They have conditions that medicine can’t fix and futures they can’t stand to consider. They’re wishing for his intervention, wanting of hope. Crossing his threshold, I’m the lucky one. I’m here.

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