Kline was interested in
depth psychology, especially theories of
Sigmund Freud, the founder of
psychoanalysis. He was also an expert in
psychometrics and carried out extensive research in the statistical analysis of
personality and
intelligence. In his 1972 book
Fact and Fantasy in Freudian Theory, widely translated, he brought these two interests together, examining the objective evidence for various ideas of Freudian theory, finding that some, but not all, were supported by the evidence. He also wrote introductory books to psychometrics, for example
An easy guide to factor analysis (1994). He was a prolific author, writing or editing at least 14 books, and over 150 scientific papers are listed under his name in
Web of Science. Among colleagues, Kline had a reputation as an opinionated controversialist who remained a genial and supportive colleague; he was revered by students for the wit and clarity of his lectures. ==Publications==