We lack a word in the English language to define significant, long-term, positive interpersonal influence - defined by this researcher as sigfluence. Sigfluence represents a fundamental will of person - paralleling Viktor Frankl’s will-to-meaning. The work first scrutinizes the autobiographies of sixteen famous contemporaries for their accounts of the people and forces that shaped their lives (and ours). The next four chapters analyze sigfluence from the academic perspectives of statistics, psychology, linguistics, sociology, and education. The last two chapters feature societal and personal applications of the new construct. The work ranges over a variety of academic disciplines, cites several hundred references, and recommends several future joint disciplinary research avenues in order to improve upon our primitive understanding of this elusive phenomenon.