This article is about the lessons that can be learned from the mistakes of the past. After a critical, constructive analysis of current theorizing and research, important directions of future personality psychology are described against the background of a general theoretical framework. It is argued that individual functioning cannot be understood or explained if the environmental factors that are operating in the individual's interactions with the environment and the biological factors that are constantly interacting with the cognitive-emotional system are not considered. Finally, the article focuses on conceptual and methodological issues that are of major importance for further progress in personality psychology, viz. (a) the match between level of psychological processes and type of data, (b) the nature of psychological phenomena studied in terms of variables, (c) the use of chronological age as the marker of individual development, and (d) the comparison between a variable and a person approach.