Y'all know we used to publish everybody's phone number in a book along with their address and then distribute copies to every household, right? We did it for many decades and it was fine. Every pay phone, which was a phone anyone with a couple coins could make anonymous calls from, had this giant book right there for your reference. Everyone knows this, right? If you didn't know someone's number you could look it up…
I'm sure not everyone knows this, because there are are people on this site who have not grown up with phone books. The article talks about a reverse phone book: according to the author, given a phone number, you are able to look up name (and profile picture). To my understanding there were no reverse-lookup phone books like that back in the day.
(Source - flea market find, a Norwegian book on the state of the art in criminology, published c. 1965)
Edit: Oh, I just remembered that locally, the athletic union published a phone book with all subscribers in the municipality listed by number.
This was c.1990 - after call ID was an option if you bought a decoder (or was an ISDN subscriber), before Internet phone directories were a thing.