Skin cancer is the most ubiquitous form of human cancer that affects more than one million Americans every year. About one in five Americans are likely to develop skin cancer at some point during their lives. It is important to get routine checkups by your dermatologist because people that have had skin cancer once are more likely to develop it again. Luckily, most skin cancers are easy to identify and treat when they are caught early. However, the longer you wait, the more dangerous the cancer becomes. There are three main categories of skin cancers that you should know about: basal cell carcinoma, squamous cell carcinoma, and melanoma.