iOS 7 represents nothing more nor less than a radical rethinking of mainstream multitouch interface. A complete visual departure from previous versions, it focuses on clarity by removing all but the most essential elements and chrome, deference by getting out of the way of content and apps, and depth by building the entire experience around a physics and particle engine that moves, blurs, parallaxes, and layers in virtual 3D. It touches every app, every pixel, and every bit of the system. It's far from perfect, and there are issues as superficial as icons and as deep as consistency yet to be overcome, but along with new features like Control Center and AirDrop, and improvements to Notification Center, multitasking, the Camera and Photos apps, Safari, Siri, and more, it's the most exciting update to iOS in years, and to mobile interface since the original iPhone. But it's also facing most competitive market ever and, given the alternatives, will it be enough?