Doing a reverse telephone number lookup is very much like detective work: you follow the trail until you find out who is the culprit. In this case, “culprit” is the person who owns that telephone number that keeps calling your number, or that number somebody gave to you the night before (but you only realize there's no name on it the day after).

It doesn't matter if it is a telephone number or a cell phone number. Most people think that the detective work can all be done if they just do a free reverse telephone number lookup on unidentified numbers. However, the fact is, you can rarely get a free service of that type, and just like when you're hiring a private detective, you need to pay. Thankfully, the cost of a reverse telephone number search is much less than the cost of hiring a PI.

So if you've been at the receiving of a prank call, reverse lookups are something to go for.

In both cases of landline and cell phone, it's not that easy to trace a number. The telemarketing companies have it easier – they just choose random names in the directory and make the call (you if you're unlucky). With a reverse lookup, you need to match a specific number to a specific name – something not very easy to do especially because, in the case of landline directories, the entries are listed by names.

Reverse lookup companies are not at all hard to find. Just search for the words “reverse lookup” and you will find results. In many cases depending on the company, you will be asked to pay a one-time payment for an unlimited number of searches. But the fees shouldn't make a big hole in your pocket. Average fees are in the range of $39 to 59.

A typical search result would yield in the owner's name, location, address telephone company. Other companies provide expanded information like the background of the owner and his or her records.

Of course, there are other ways that you can do a reverse lookup. They are free but they would cost more in time and in most cases it becomes a hit or miss situation. One thing you can do is search for the number on search engines like Google, Yahoo or MSN. If the number has been entered into one of the indexed websites, you should be able to find some leads on who has been calling, if not find the matching name to the number during the first search.

Another thing that you can do is to sign up with a free cell phone directories, but the information you'll find there are those that have been volunteered by the members. To access these websites, you have to register for free and, of course, volunteer your name and cell phone number.

All things being considered, the sheer accuracy of information and the extensive database should tip the balance in favor of paid reverse lookups. The small fee charged to do a reverse lookup is more than worth it.