H∞-Control Theory: Lectures given at the 2nd Session of the Centro Internazionale Matematico Estivo (C.I.M.E.) held in Como, Italy, June 18–26, 1990

Sunscreen can be a smokescreen. Sunscreen is unlikely to stop you from being sunburned, or to reduce your risk of developing skin cancer. That’s because most people don’t apply it properly, and stay in the sun too long. The solution? Slather on sunscreen daily and reapply it often, especially if you’ve been in the water. How much? At least enough to fill a shot glass.