This morning I get into the office and there’s an envelope addressed to me sitting on my desk.

The return address says “Horowitz”, Physics Dept, Cambridge, MA. I don’t know a Horowitz, but it looks like a Harvard address, so I’m intrigued.

I open it up.

Inside I find an article from The Astrophysical Journal, published in 1993. The authors are Paul Horowitz and Carl Sagan.

At the top there’s a handwritten note, signed Paul Horowitz. And on the first page there’s a highlight behind “37 candidate events”.

People have often asked us what 37signals means. Our original web site explained the origin of the name.

And now, because of the generosity of Paul Horowitz himself, we have a signed copy of the actual article where the 37 signals were first mentioned. Here’s a PDF of the article if you’d like to browse the whole thing.

What an unexpected and wonderful surprise, and another great example of unrelated events coming together to produce something you never expected.