Ask HN: How to find current phone numbers?

Write them a letter and ask them :)

The one time I tried that, it worked.

How often do you have this problem? The easiest solution might be to mail them / show up at their door (startup idea?)

I often want to contact people about old research, but they have changed institutions or retired. I can usually find their most recent address, but no working phone number, and they usually have no social media presence.

It is ironic that the fallback method for cold-contacting people in the Internet age has to be snail mail.

At this point, social media is the wayto get ahold of people. Not having social media in 2023 is like not having a phone number in 1990