They are the 25 most influential people of the past 25 years -- those who changed our world, transformed technology, mapped the human body and affected the way we relate to one another.
1. Bill Gates, software entrepreneur
His Microsoft software shaped the way millions use the technology that has transformed communications and commerce -- making him the world's richest man and, now, a leading philanthropist.
2. Ronald Reagan, 40th U.S. president
Elected in 1980 and re-elected in 1984, he put the United States on a more conservative course, restored buoyancy and confidence in the presidency and forged a partnership with a reformist Soviet leader who helped end the Cold War.
3. Oprah Winfrey, talk show host
As a talk show host, first at WLS-TV's AM Chicago in 1984, she pioneered a form of intimate public discourse that brought taboo subjects into the open and sparked a confessional, self-help culture.
4. & 5. Francis Collins & J. Craig Venter, mappers of the human genome
The Human Genome Project headed by Francis Collins with a parallel private effort by Celera Genomics under Craig Venter jointly announced the mapping of the human genome in 2000, opening the door to breakthroughs in identifying, treating and preventing the world's most-feared diseases.
6. Osama bin Laden, terrorist
For most Americans, the attacks of Sept. 11, 2001, by the al Qaeda network he leads marked the beginning of a global battle against radical Islamists 12 years after the fall of the Berlin Wall marked the end of the Cold War.
7. Stephen Hawking, physicist
In the tradition of Isaac Newton and Albert Einstein, he explored the nature of the universe. He popularized science, wrote the best-selling "A Brief History of Time" in 1988 and remains a puckish personality despite being severely disabled by Lou Gehrig's disease.
8. Lance Armstrong, cyclist and cancer activist
He won a record-breaking seven consecutive Tour de France races, cycling's most prestigious event, after battling testicular cancer. Sales of his iconic "Livestrong" wristbands have raised millions of dollars to help fight cancer.
9. Pope John Paul II
Polish-born Karol Jozef Wojtyla helped propel a peaceful revolution in Poland in 1989 that ended Soviet domination and reverberated through Eastern Europe. In a 26-year papacy, he redefined the Roman Catholic Church's role in modern times.
10. Bono, rock musician and activist for Africa
Born Paul Hewson, the lead singer of the Irish rock band U2 has shrewdly pressed world leaders to forgive Third World debt and address the AIDS pandemic in Africa.
11. Mikhail Gorbachev, Soviet leader
The last leader of the Soviet Union, from 1985 to 1991, he introduced economic and political reforms -- glasnost and perestroika -- and forged a partnership with an anti-communist U.S. president. On Gorbachev's watch, the Berlin Wall fell and the Soviet Union dissolved.
12. & 13. Sergey Brin & Larry Page, co-founders of Google
After meeting as doctoral students at Stanford in 1995, they devised a way to organize information on the Internet by analyzing relationships between Web sites. Google is now the Web's most-used search engine -- so familiar it's become a verb.
14. George W. Bush, 43rd president
Taking office after a 5-4 Supreme Court decision settled the 2000 presidential election, he led America's response to the terror attacks of Sept. 11, 2001, and ordered the invasion of Iraq in 2003 -- engaging the United States in its longest war since Vietnam.
15. Sam Walton, retailing pioneer
A farm boy from Oklahoma who started his retailing empire with Walton's Five and Dime in Bentonville, Ark., he relied on high-volume and low markups to build the world's biggest retailer -- and swamp the competition.
16. Deng Xiaoping, Chinese leader
The de facto leader of China from 1978 into the 1990s, he opened the nation to global markets and economic modernization through "socialism with Chinese characteristics" -- and cracked down on Tiananmen Square protesters in 1989.
17. Michael Jordan, basketball star
Arguably the greatest basketball player of all time, mostly for the Chicago Bulls, his athletic leaps and slam dunks influenced a generation of players. With a likeable persona, he also led all leagues in lucrative endorsements.
18. Howard Schultz, Starbucks entrepreneur
A poor kid from Brooklyn who wanted to replicate Italian espresso bars, he cultivated a chain of coffeehouses that have influenced many Americans' daily habits and tastebuds much as Ray Kroc's McDonalds did a generation earlier.
19. Nelson Mandela, anti-apartheid leader
Released in 1990 after 27 years in prison, he preached reconciliation and was the first elected president of a fully democratic South Africa.
20. J.K. Rowling, author
Her first Harry Potter book, completed in 1995 and initially rejected by several publishing houses, launched a seven-volume series that absorbed children and adults in complicated fantasies spanning thousands of pages.
21. & 22. Bill & Hillary Clinton, 42nd president & N.Y. senator
He was the first Democrat elected to two terms in the White House since Franklin Delano Roosevelt, then survived impeachment. She went from wronged wife to New York senator to the most viable female presidential contender in U.S. history.
23. Russell Simmons, hip-hop pioneer
He helped popularize a distinctively American form of music -- co-founding the hip-hop label Def Jam -- that has influenced mainstream pop culture, from music to dance to dress, since the mid-1980s.
24. Ryan White, the face of AIDS
The 13-year-old hemophiliac from Kokomo, Ind., was diagnosed with AIDS in 1984, then banned from attending his public middle school. A human face for a stigmatized disease, he died in 1990.
25. Homer Simpson, Everyman
The doughy star of the animated TV series "The Simpsons" epitomized the irony and irreverence at the core of American humor -- the same force that helped make "The Daily Show's" Jon Stewart a major source of news for young people.