The NAAJ is honoring the Society of Actuaries on its golden anniversary in 1999 by publishing a series of articles on the contributions of actuaries to the development of ideas. In this issue, the second of the series, we explore the development of the credibility idea and the relationships of this development to deep issues in the methodology of science. We begin with a short essay by James C. Hickman and continue with comments by three actuaries who were deeply involved with the development of credibility: Robert A. Bailey, Hans Buhlmann, and Chrles C. Hewitt. From NAAJ, April 1999, Volume 3, Number 2.