Why, the phone book, of course. Usually the yellow pages, if you were in a reasonably sized metropolis. Nobody used a dictionary; I can’t imagine where this misinformation came from.

The advantage of using a phone book was that a new one was delivered, completely for free, every year, so you just had to hang on to an old one if you were particularly fastidious, and otherwise just used the current one. And they were softbacks, so were more comfy to sit on than a hardback dictionary. Not to mention that not all households had a dictionary, while I seem to recall that the market penetration of landlines was something like 98% of American households (with subsidization for poorer folks) and they all had phone books; both were pretty much necessary to carry on a normal life.

Now, let me tell you about paper roadmaps, and how they were available for free at pretty much all gas stations (though the ones at Esso were considered the best), on a little rack near the door. No problem perusing the selection while your gas was pumped and oil checked by the attendants. (And there was no food or candy available to buy, so your other options for amusement were pretty limited).