Bradley, E.,Motter, A. E.,Pecora, L. M.
Excerpt from the introduction: Articles in this anniversary issue offer expert insights about the past, present, and future of nonlinear science. The authors of these invited papers were asked to share their personal opinions about interesting, important, and surprising developments in the field, identify the current challenges, and look into their crystal balls to predict what might happen in the next 25 years. Some of the resulting papers are reasonably technical; others offer high-level reviews and perspectives. All are deeply thoughtful. As authors were given considerable latitude to express their personal opinions and views, some papers have remarks that might normally be outside the bounds of standard scientific papers. We hope the readers will enjoy these personal opinions and, perhaps, be stimulated to think differently about their own areas of research.