There is lots of water on earth, but 97% of it is too salty for human consumption. As concern grows over water's scarcity, there is growing interest in desalination, which turns salty water into fresh water. How does it work, and can it provide a quick technological fix?

Also in this Technology Quarterly report:

Rational consumer: Changing gears - New types of gearbox explained

Computing: Digital models of buildings - From blueprints to databases

Wave power: The coming wave - A story of ups and downs

Case history: Tapping the oceans - The rise of desalination

Telemedicine: The future of health care - It may be closer than you think

Opensource - hardware: Open sesame - The virtues of letting everyone in

Brain scan: Truth and consequences - A profile of Jimmy Wales, the cofounder of Wikipedia