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."
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."