On Answers

Four kinds of search engines.
By Jason Pontin

Contributors

Letters From Our Readers

Potemkin Trading

Cap-and-trade alone won't curb emissions.
By David Victor

Cell Fate

Why we can't abandon embryonic stem cells.
By Jeanne Loring

To Search, Ask

Library science will improve online search.
By Daniel Tunkelang

Privacy Requires Security, Not Abstinence

Protecting an inalienable right in the age of Facebook.
By Simson Garfinkel

Allison Macfarlane

A nuclear expert on life after Yucca.
By David Talbot

Igniting Fusion

Researchers at the Lawrence Livermore National Lab will try to start self-sustaining fusion reactions using the world's largest lasers.
By Kevin Bullis

Fusion Reactions Using Massive Lasers

Cloud Computing

Cloud computing has changed how software is developed and used, creating a host of new online services for businesses and consumers.

Carbon Trading on the Cheap

If the United States wants to build a market-based approach to reducing carbon dioxide emissions, it should learn from Europe's failures.
By Peter Fairley

A Pound of Cure

The federal government is about to spend big on health-care IT. Too bad the medical industry has a vested interest in inefficiency.
By Andy Kessler

Building NASA's Future

The U.S. space agency readies the first test flight of the vehicle destined for the moon.
By Brittany Sauser

Construction of the Ares I-X Rocket

Biomedicine

Information Technology

Materials