ARE YOU EVERYTHING YOU SAY YOU ARE?... ON ABC NEWS� �20/20,� FRIDAY, JANUARY 20

* Female Author Goes Undercover to Infiltrate Man�s World;

* How True Are Natural Remedy Claims Made by Infomercial King?;

* The Art -- And History -- of Hoaxing

What�s it like to be one of the guys? In search of an answer, female author Norah Vincent did a complete transformation from head to toe to go �undercover� as Ned Vincent, successfully infiltrating the inner sanctum of a man�s world. From boys� bowling night out to the art of picking up/dating women to buying a car � and even living as a monastery trainee and attending a men�s-only therapy group -- Vincent was able to experience the world women rarely get to see. �I wanted to enter males� spheres of interest � and see how men are with each other. I wanted to make friends with men.

I wanted to know how male friendships work from the inside out,� Vincent tells ABC News correspondent JuJu Chang in her first televised interview since writing a book, Safe Made Man, about her secret experiment. Vincent tells Chang what she extracted from being a man � and her revelations may surprise you. Additionally, she allows �20/20� cameras to document portions of her experience and also tells �20/20� how she achieved the convincing look of a man, from wardrobe and makeup to acting classes. �This wasn�t just a stunt� It was about finding something out about the human creature, and I learned it the best possible way because I went through it.� The exclusive report airs on �20/20,� FRIDAY, JANUARY 20 (10:00-11:00 p.m. ET) on the ABC Television Network.

And: Kevin Trudeau has been on the bestseller list for six months and says he has sold five million books on natural remedies that he says can prevent and cure virtually every disease. His infomercials filled 2000 hours of airtime last year. But who is this infomercial king who has made a fortune selling the unproven, and why do so many people follow his claims� some of which have been called fraud by the government? John Stossel reports.

Also: Hoaxing -- it is one of the oldest games people play� we are not who we seem to be. People have been playing it for sex, power, ego and money for centuries. So why is it sometimes so easy to play with the truth, and what are the classic ingredients of a successful hoax? To find out, Bob Brown looks at notorious hoaxes, including recent headline-making ones like the finger in a container of Wendy�s chili.

�20/20� is anchored by Elizabeth Vargas and John Stossel. David Sloan is the executive producer.