The popular conception of science is of a steady, upward climb of progress. The reality is not that simple. Highly significant discoveries often stay unrecognized for decades, particularly if they conflict with the current paradigm or extend it in ways hard to imagine at the time. Since Volume 1 of Ahead of the Curve, the editors have continued to collect papers they believe are important scientific contributions and have gotten lost due to the sheer volume of data and the dominance of the latest trend, whatever it may be. The pioneers in this book took such creative leaps that they essentially started new branches of inquiry.