The Mars Pathfinder Mission

Last summer the first ever Mars rover found in situ evidence that the Red Planet may once have been hospitable to life

The Split Brain Revisited

Groundbreaking work that began more than a quarter of a century ago has led to ongoing insights about brain organization and consciousness

The Single-Atom Laser

A new type of laser that harnesses the energy of individual atoms reveals how light interacts with matter

Mating Strategies in Butterflies

Butterflies meet, woo and win their mates using seductive signals and clever strategies honed by evolution

Léon Foucault

Celebrated for his pendulum experiment in 1851, Foucault also produced decisive evidence against the particle theory of light, invented the gyroscope, perfected the reflecting telescope and measured the sun's distance...

Defeating AIDS: What Will It Take?

HIV 1998: The Global Picture

Worldwide, the populations most affected by the AIDS virus are often the least empowered to confront it effectively

Improving HIV Therapy

Today's optimal treatments can work magic, but they are costly and onerous and do not work for everyone. What might the future bring?

How Drug Resistance Arises

Viral-Load Tests Provide Valuable Answers

When Children Harbor HIV

HIV infection is particularly difficult to combat in the young

Preventing HIV Infection

Altering behavior is still the primary way to control the epidemic

HIV Vaccines: Prospects and Challenges

Unlike vaccines for many viruses, those for HIV may have to go beyond generating antibodies. Devising approaches that will fully activate the immune system is far from simple

Avoiding Infection after HIV Exposure

Treatment may reduce the chance of contracting HIV infection after a risky encounter