Dr. Katz: There are many ways to protect oneself. One has to be reasonable in what you want to do. But you avoid the midday sun, for example, from 10:00 to 2:00, if you can. If you can't, you protect yourself. Protect yourself with a hat. You protect yourself with sunscreen. Sunscreens do work. Some sunscreens work better than others and that has to be the choice of the individual. But certainly, you want to start with an SPF of at least 15. Which means when one talks about SPF, the question is that's a sun protection factor. And the sun protection factor, that protects you from ultraviolet B and it attenuates the sun. That is, it doesn't protect you completely, it just decreases the amount of each ray by 15 times for an SPF 15 or an SPF 30 decreases it by 30. It doesn't mean that you won't get sunburned if you used it all day long.