"I saw it as a special place when I first went there," Conaway said in a phone interview from his home in the foothills of Virginia's Blue Ridge Mountains. "But it has become jaded, and I guess I have, too." Conaway has been visiting Napa for more than three decades, first as a wine columnist, more recently as a freelance writer. His principal muse has been the valley's evolution from quiet agricultural enclave to the nation's most precious and popular wine region. ... From his visits he has harvested three books: "Napa: The Story of an American Eden" in 1990; "The Far Side of Eden: New Money, Old Land, and the Battle for Napa Valley" in 2002; and now "Napa at Last Light: America's Eden in an Age of Calamity" (Simon & Schuster, 336 pages, $26), to be released March 6.