Leatherman, 50, a coastal geomorphologist at Florida International University in Miami, spends about three months of the year away from his real job—the study of coastal erosion—checking out beaches with his wife, Debbie, and their 7-year-olds Steve and Sandy. "I don't think I've seen a mountain in 15 years," he says.
Dr. Leatherman became Dr. Beach—a nickname coined by a former student—when a reporter for Condé Nast Traveler called him in 1989 and asked him to name his favorite beaches. Leatherman rattled off 10—and became a minor celebrity with a dream sideline. "Americans are crazy about beaches," he says, "and they're crazy about Top 10 lists."
The roster was released in conjunction with Leatherman's new book America's Best Beaches. (His No. 1 choice for '98: Kailua Beach Park on Oahu.) In it he assesses 50 factors, including sand quality, crowding and beach width. And no frivolity, please. "Bikinis per mile," he says, "is not one of my criteria."