It is possible to find out who lives at an address by consulting the telephone directory. Telephone directories exist as hard copies, and these are distributed for free in most areas. They are also available online and can be accessed for free.
The beginning of the 21st century has seen the introduction of telephone directories in the form of smartphone applications. The business page listings are often referred to as the "yellow pages," while private residential listings are known as the "white pages." White page entries are in alphabetical order based on surnames, or last names. Online, it is possible to do a "reverse" search by address on websites like whitepages.com/reverse_phone or dexknows.whitepages.com/reverse_phone. The first telephone directory was printed in 1878 in the United States.