What is the best free way to find out someone's family history and backgroun

Question:It needs to be very comprehensive but only covering the last hundred years so please help.

Best Answer - Chosen by Asker: It needs to be very comprehensive but only covering the last hundred years so please help.

Stop being nozey.. Kiddin u can go to National Libraries and trace people my friend...

Ask your relatives?

log on to, www.ancestry .com

In the world of Genealogy nothing is easy, and your question is not easy. Births,marriages,and deaths in the last 100yrs can be found[and that is as comprehensive as it gets] at Family Record Centres in the areas where the events took place.If you need to go deeper it has already been said ask relatives.

Most of the free genealogy is about people born before 1930. We hide facts about living people to protect their privacy.

Some questions, like "How can I get the University of Denmark's Women's Gymnastic team to come over to my house for an orgy?" or "How can I keep on eating bacon double cheeseburgers from my recliner, lose weight and get rock-hard abs?" don't really have any good answers.

You'd have to start with the person, find his/her parents, and work backwards, using interviews, obituaries, high school year books, census images, personnel records from corporations and so forth.

If the person in question is up for a Federal Judgeship and you are an FBI agent, ask your supervisor. If the person in question is you, and this is a school project, start calling your grandparents. Apologize for not calling and writing more often. Start interviewing. If the person is a stranger, you'd need to hire a private investigator.
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Added after you added details:

You'd have to trace both people back to a common ancestor, using non-web sources until you got to people born in the 1800's. If you got to 1700 and still no common ancestor, you could reasonably assume their relation wasn't close enough to call.

If the well-known UK person had a fling and swore the mother of his love child to secrecy, and she kept that secret through love, blackmail, or intimidation, you would not find it unless you had the resources of a very good detective at your disposal.

By "Very comprehensive" I thought you meant religion, politics, occupation, views on the Monarchy and strong drink and so on; the stuff biographies are made of.

I still don't think you're going to be able to do it free and easy.

Free and easy is not quality genealogy.

OVERALL..
standard is that living persons have the right to their own privacy. Because of that... the last 100 years will be HARDER to locate than historical records. Any of us are entitled to OUR OWN records, but not that of someone else.
It sounds like you are looking for not just one living person, but two.. you have to know both, in order to locate a common link. In addition, many celebrities and such, make an effort to keep personal info private, since they don't like being harassed.
Even with 'common' genealogy, it isn't free (nor should it be).
There MIGHT be means to find what you want.. but don't expect it.

If it is a well known UK person there may a biography written or even someone may have done their family history already. But nothing is free in this world and you would probably directly or indirectly end up paying.

If the person you know was resident in a County for a long time such as the Lord of the Manor, a duke, duchess etc try looking in the area they lived in. Many historic houses have records some in situ some at local family history libraries or large county libraries.

Easiest one go to Google and put the name in, same for Wikipedia.

The Freedom of Public Information Act stops you from finding out about peoples background for the past 100 years in the UK, whether they are a well known person or not. Privacy laws are put there to stop people prying, and in fact stealing other peoples identity. Unless you are directly related to a person, and can prove it you will not be able to apply for their birth, marriage information.
I am afraid you will just have to ask family for information, or alternatively contact the famous person, and ask them, they may be really intrigued, and wish to trace all their spread out family. After all just because they are well know doesn't mean to say they are not like us wanting to know our ancestors, and relatives.