It is written in the hope that I can instill in a new generation of psychologists the love for quantitative methodology imparted to me by reading the popular and then later the scientific texts of Ray Cattell [Cattell, 1966b] and Hans Eysenck [Eysenck, 1964, Eysenck, 1953, Eysenck, 1965]. Those Penguin and Pelican paperbacks by Cattell and Eysenck were the first indications that I had that it was possible to study personality and psychology with a quantitative approach.
My course in psychometric theory, on which much of this book is based, was inspired by a course of the same name by Warren Norman. The organizational structure of this text owes a great deal to the structure of Warren's course. Warren introduced me, as well as a generation of graduate students at the University of Michigan, to the role of theory and measurement in the study of psychology. He introduced to me to the "bible" of psychometrics: Jum Nunnally's Psychometric Theory [Nunnally, 1967].
The students in my psychometric theory classes over the years, by their continuing questions and sometimes confusion, have given me the motivation to try to make this text as understandable and useful as I can. The members of the Society of Multivariate Experimental Psychology, by their willingness to share cutting (and sometimes bleeding) edge ideas freely and with respect for alternative interpretations have been a never ending source of new and exciting ideas.
This book would not be possible without the amazing contributions of the R-Core Team and the many contributers to R and the R-Help listserve.