This paper reviews the evolution of measurement and evaluation in libraries from the perspectives of three important figures who have shaped the history of library assessment activities: James Gerould, F. Wilfrid Lancaster, and Duane Webster. Although Lancaster is about a decade older than Webster and almost half a century removed from Gerould, the contributions of the three individuals knit a common fabric in the development of assessment in libraries in the past century. In investigating the interconnections of the three individuals, not only can we gain an understanding of how we got to today???s world of evaluation in libraries, but also we can gain a glimpse into future developments in the field. James Gerould was a library a...