For some, this year in science may be remembered more for its disasters than its successes. On January 16 the space shuttle Columbia launched to great fanfare, only to fail tragically on re-entry 16 days later. Then came news of the mysterious and lethal disease known as SARS, which sparked worldwide panic. And a midsummer blackout stretching from Ontario to New York served as a vivid reminder of how dependent we are on a fragile power grid.

Amid these calamities, however, a number of noteworthy achievements unfolded. China became the third nation to send people into space; paleontologists working in Ethiopia unearthed the oldest known members of our species; researchers applied virtual reality to colonoscopies and autopsies with stunning results. In addition, the 50th anniversary of the discovery of the structure of DNA and the centennial of powered flight served as springboards for reflection on the bigger picture of scientific progress.

Below, and in no particular order, are 25 of the stories that most impressed us here at Scientific American.com. Some are included on the basis of their significance, others for sheer fun. --The Editors

Skulls of Oldest Homo sapiens Recovered

Gecko-Inspired Adhesive Sticks It to Traditional Tape

SARS: Caught Off Guard

China's Great Leap Upward

Four-Winged Dinosaur and the Dawn of Flight

New Drug May Mitigate Peanut Allergy

Healing the Grid

The Infant Universe, In Detail

The Cold Odds against Columbia

Pet Prairie Dogs Suspected in U.S. Monkeypox Outbreak

New Study Finds Agent Orange Use Was Underestimated

Large Fish Populations Imperiled

Harvesting Hydrogen Fuel from Plants Gets Cheaper

Mare Gives Birth to Own Clone

Electronic Paper Speeds Up for Videos

Number of Threatened Species Tops 12,000

Autopsies, No Scalpel Required

100 Years of Flight: The Equivocal Success of the Wright Brothers

Ink Analysis Smudges Case for Forgery of Vinland Map

Scientists Discover New Frog Family

E-mail Study Corroborates Six Degrees of Separation

Celebrating the Genetic Jubilee: A Conversation with James Watson

Astronomers Find Most Ancient Planet Yet

Decaf Coffee Plants Developed

Claim of Nonhuman-Induced Global Warming Sparks Debate