The growing interest in research on temperament during the last decade has been re- corded by several authors (e. g. , R. Plomin; J. E. Bates) from such sources of informa- tion as the Social Sciences Citation Index or Psychological Abstracts. The editors’ inquiry shows that the number of cases in which the term temperament was used in the title of a paper or in the paper’s abstract published in Psychological Abstracts reveals an essential increase in research on temperament. During the years 1975 to 1979, the term temperament was used in the title and/or summary of 173 abstracts (i. e. , 34. 6 publications per year); during the next five years (1980-1984), it was used in 367 abstracts (73. 4 publications per year), whereas in the last five years (1985 to 1989), the term has appeared in 463 abstracts, that is, in 92. 6 publications per year. Even if the review of temperament literature is restricted to those abstracts, it can easily be concluded that temperament is used in different contexts and with different meanings, hardly allowing any comparisons or general statements. One of the consequences of this state of affairs is that our knowledge on temperament does not cumulate despite the increasing research activity in this field. This situation in temperament research motivated the editors to organize a one- week workshop on The Diagnosis of Temperament (Bielefeld, Federal Republic of Germany, September 1987).