A reverse phone directory is a collection of phone numbers and customers details. A phone directory contains customer's details (such as name and address) that allow user' to lookup telephone numbers with the help of their name, whereas a reverse phone directory allows to retrieve customer's details with the help of a phone number. However these services are basically used in law enforcement and emergency services. Reverse phone lookup includes both public and private accesible directories services. Public accessible directories are phone directories provided by telecommunication service providers and private accessible directories are created with the help of information provided in the public directories and it's enabled with search option that allow to lookup phone numbers. These services allow to lookup cell phone number as well as phone numbers in order to find a detail.