Healthy skin handbook: everything you need to know.

You're aware that the sun causes dark spots and fine lines, but it's also behind a very scary threat to your health: skin cancer. With rates skyrocketing in young women, it's crucial that you stay safe.

Sure, you've heard the warnings: Wear sunscreen, cover up at the beach, skip the tanning bed. Still, even though these sun-safe pronouncements are so prevalent, a lot of women disregard the message. Only 34 percent of young adults under 25 say that they regularly use sunscreen, reports a 2003 survey from the American Academy of Dermatology.

If you're part of the sans-sunscreen group, then we need to clue you in to something: You're basically inviting skin cancer. Consider the fact that just five sunburns at anytime in your life double your odds of developing it.

Yes, it sounds harsh, but that's because it is. Skin cancer is the most prevalent of all cancers. Melanoma, the deadliest form of the disease, is now the second most common cancer in women between the ages of 20 and 29, according to the American Cancer Society. And rates of basal-cell carcinoma and squamous-cell carcinoma--the two less lethal forms of the disease--have more than doubled in the past generation among 20- and 30somethings, reports a 2005 study from the Mayo Clinic.

It's enough for many dermatologists to consider skin cancer to be at record levels. "When I first started practicing 20 years ago, skin cancer was a disease of senior citizens--even seeing someone in her 30s with it was unusual," explains Richard Fried, MD, PhD, clinical director of the Yardley Skin Enhancement and Wellness Center in Yardley, Pennsylvania. "Now, I regularly remove skin cancers from 20- and 30somethings, and sometimes even teens, and I barely bat an eye."

The skin-cancer surge can mainly be chalked up to our sun-worshipping culture, explains James Spencer, MD, clinical professor of dermatology at Mount Sinai School of Medicine in New York City. A major part of this is the popularity of tanning salons. Several studies have linked indoor tanning to all three skin-cancer types, and yet young women are still cooking themselves under sunlamps--convinced they look thinner and healthier with a year-round bronzing, says Dr. Spencer.

And here's the crazy thing: Skin cancer is almost 100 percent preventable--if you strike a balance between enjoying the great outdoors and cutting your risk factors. But before you can commit yourself to taking the necessary steps, it helps to know the myths about what does and doesn't lead to sun damage. Your primer for practicing safe sun starts here.