Whether people believe in astrology or not, nearly everyone knows his or her sign.
Some think the way the stars, sun and moon were aligned when you were born is the key to unlocking the mystery of your personality.
According to a 2001 Gallup poll, 33 percent of Americans believed in astrology and the National Science Foundation said that 43 percent of Americans checked newspaper horoscopes.
If so, they are in good historical company.
Alexander the Great and Galileo both took heed of the stars.
The study of astrology dates back thousands of years, but experts cannot seem to agree on exactly when or where it began. Some say it originated in 2,300 B.C. in Mesopotamia or modern-day Iraq; others say 4,500 B.C.
Some say it began in Egypt.
Whatever its origins, the study is an important tool for life, astrologers say.
"First of all, astrology is based on mathematical cycles," said Susan Miller, who writes an astrology column for InStyle magazine and CosmoGirl.
"You have complete control of your life. I can just tell you the kind of influences, whether they are tough and constricting, or open and expansive. We feel you should take advantage of the good ones, and I show you how to deal with the difficult ones. It is a matter of adjusting for the flow of the cosmos."
Billionaires and Presidents
Miller, who created the Web site Astrologyzone.com, said that certain signs were predisposed to attain certain things in life.
For example, five U.S. presidents have been Scorpios and five have been Aquariuses.
"Aquarius wants to change the world to make it a better place. President Lincoln was an Aquarius. You see this sign coming up a lot. This is almost the sign of the mom that's so busy taking care of battered women and she forgets to cook dinner at home. It is a very giving sign," Miller said.
Presidents John Adams and Teddy Roosevelt were both Scorpios, who are considered good negotiators, according to Miller.
Sen. Hillary Rodham Clinton, D-N.Y., is also Scorpio, she noted.
A Forbes magazine study found that more billionaires were Virgos than any other sign.
Warren Buffet, who recently pledged 85 percent of his more than $40 billion fortune to charity, is a Virgo.
Miller said that Pisces had been the dominant billionaire sign until a few years ago.
"Pisces and Virgo are on the same axis. They are 180 degrees apart," she said. "These are two signs who don't care about money as the primary endpoint. They care more about service to others and the product itself. Maybe there is a lesson in that."
Miller said that Buffett and Bill Gates, who is a Scorpio, both had Jupiter aligned with Pluto, even though they were not the same sign and were born 25 years apart.
Unfortunately for Geminis, Miller said, they are the most accident-prone sign.
Geminis, she said, are easily distracted and constantly multitasking. Angelina Jolie is a Gemini, which explains why she has interests in so many areas.
Miller said that Gemini was also the sign that rules communication, and that Jolie had made a second career of raising awareness about the plight of refugees.
President George W. Bush, who turns 60 on Thursday, is a Cancer, which Miller said meant that he thrived on a group dynamic and was also quite family oriented.
"Whenever you have a birthday close to the country's that you are serving or even the company that you work for, that's significant," Miller said. "You know, there's some kind of destiny point there."
Interestingly, Miller said that television news anchors tended to be Capricorns -- that includes Katie Couric, Matt Lauer, and ABC News' Diane Sawyer.
"Capricorns, they are hardworking. They are reliable and are going to show up at 4 a.m. in the morning. They are going to rewrite the copy. They are going to be thorough. You can count on them."
Sagittariuses are also prominent among television news anchors.
Among them are ABC News' Robin Roberts and Bill Weir.
"That's the sign of the whole truth and nothing but the truth," Miller said. "It is a sign of dissemination of information."
What's Your Sign?
Aries (March 21 - April 19) The Aries symbol is the ram. Aries represents the beginning of all things because it is at the beginning of the astrological chart.
Taurus (April 20 - May 20) The symbol is the bull, which signifies its stubborn nature.
Gemini (May 21 - June 20) The symbol is a mythological set of twins, which describes its dual nature.
Cancer (June 21 - July 22) The symbol is the crab, which describes the sign's protective and defensive qualities.
Leo (July 23 - Aug. 22) Leo is represented by a lion, which signifies control and power.
Virgo (Aug. 23 - Sept. 22) The symbol of the virgin represents its structured and organized personality.
Libra (Sept. 23 - Oct. 22) The sign's symbol of scales represent the Libra's desire for fairness and a balance in life.
Scorpio (Oct. 23 - Nov. 21) The Scorpio's symbols are the Scorpion and the Eagle, which signify the sign's defensive and wavering emotions. It is the only astrological sign with two symbols.
Sagittarius (Nov. 22 - Dec. 21) The archer, which is half man, half horse, characterizes the Sagittarian ability to seek eternal knowledge and to philosophize.
Capricorn (Dec. 22 - Jan. 19) The goat symbol describes its ambition and drive.
Aquarius (Jan. 21 - Feb. 19) The water bearer symbol represents the sign's wisdom and truthfulness.
Pisces (Feb. 20 - March 20) The fish symbol represents its constant motion (physically and mentally) and its free nature. Pisces represents the end of all things because it is at the end of the astrological chart.