Book excerpt: In the aftermath of a shattering illness, Lonni Sue Johnson lives in a "perpetual now," where she has almost no memories of the past and a nearly complete inability to form new ones. The Perpetual Now is the moving story of this exceptional woman, and the groundbreaking revelations about memory, learning, and consciousness her unique case has uncovered. Lonni Sue Johnson was a renowned artist who regularly produced covers for The New Yorker, a gifted musician, a skilled amateur pilot, and a joyful presence to all who knew her. But in late 2007, she contracted encephalitis. The disease burned through her hippocampus like wildfire, leaving her severely amnesic, living in a present that rarely progresses beyond ten to fifteen minutes. Remarkably, she still retains much of the intellect and artistic skills from her previous life, but it's not at all clear how closely her consciousness resembles yours or mine. As such, Lonni Sue's story has become part of a much larger scientific narrative—one that is currently challenging traditional wisdom about how human memory and awareness are stored in the brain. In this probing, compassionate, and illuminating book, award-winning science journalist Michael D. Lemonick uses the unique drama of Lonni Sue Johnson's day-to-day life to give us a nuanced and intimate understanding of the science that lies at the very heart of human nature.