There are many reasons someone wants to know who is hiding behind a phone number and decided to learn how to reverse phone numbers. Performing a phone reverse look up could occur in the following situations: Recurring prank calls Harassing telemarketers Suspecting your spouse of cheating on you These are the most common occasions when you very much would like to identify the person on the other side of the line and try to reverse a phone number. If the call is made from a listed phone number it is an easy task, you could just use a free service widely available on the web. But do you think your spouse's lover is dumb enough to call from his/her home phone? Chances are all these unwanted phone calls are made from either unlisted land lines or cell phones lines. And all the data related to these phone numbers are private data not available by any free directory. There are companies specialized in phone data gathering and mining. They buy databases from phone and cellphone companies and resell private information on the phone numbers owners. It is a legitimate business. Of course you'll have to pay to access these information. Did I say it is a business? Fees are reasonable: a single phone number look up report is worth around 15 dollars and a yearly membership will cost you 40 dollars, which enables you to perform as many reverse phone look ups you may need. You'll just have to type the 10 digits of the number you want to perform a reverse look up on and quickly you'll be provided with the name of the phone number owner, his/her address, information about his/her household. Everything you need to take action and stop the mysterious calls. So, if you think your peace of mind is worth something between 15$ and 40$, learn how to reverse phone numbers, even unlisted or cellphone numbers. For more info one of the most up-to-date and trustworthy reverse phone look up service just visit How To Reverse Phone.