In the early days of phone service, you'd call the operator and ask to be patched through to a particular line. This system was first questioned in 1879 by Alexander Graham Bell's friend, Dr. Moses Greeley Parker of Lowell, MA. The town was suffering from an epidemic of measles and the doctor quite sensibly suggested that if the town's phone operators fell ill, replacement operators would struggle to run the system. Numbers instead of names was seen as a better solution which, as you all know, is the system we still use today.
You'll also find out how they assign area codes, why 911 is the emergency number in the US, and more. Link -via Bits and Pieces