Discovery News informs me about the only known edition of the world’s first telephone book, newly discovered in Connecticut:
“The 20-page directory was issued in November of 1878, just two years after Alexander Graham Bell invented the telephone. The phone book contained information useful to 391 subscribers within the New Haven, Conn., area who were obviously still learning their way around the new communication device.
“‘Should you wish to speak to another subscriber you should commence the conversation by saying, ‘Hulloa!'”” it instructs.”