Trends once held sway for seasons, even years. Now they're stale within weeks—or however long it takes for them to trickle down to your Aunt Marge's Pinterest board. A new e-commerce site offers a refreshing solution through its focus on "quintessential things": enduring stuff that you won't grow tired of after a few uses. Launched this week, The Line is stocked with a tightly edited assortment of clothing, furniture, homegoods, beauty products, and books from established and emerging brands including Reed Krakoff, Mason Pearson, KPM Berlin, and elegant newbie fashion label Protagonist. Where else can you find Phaidon's Alexey Brodovitch monograph, the perfect t-shirt, and a toothbrush made of magical Japanese charcoal?