Door of Knowledge

"A few weeks ago I sold a table saw to a random handyman from Queens. He drove down to pick it up in a neatly outfitted handyman van, a scuffed-up and worked-in vehicle with built-in cabinets lining the port bulwarks and a shiny lumber rack mounted to the roof. The van was nice, fine, a characteristic example of a mobile workshop, but what struck me about it was the Door of Knowledge scrawled inside the passenger side rear door.

"This fellow said that the Door of Knowledge preceded his ownership of the vehicle, and didn't seem to have much understanding of the principles embodied in it. But I loved it."