This book covers the details of the study which analyzes the relationship between users' characteristics and users' interface preferences. An online survey is developed for this study. This survey composed of two types of questions: (1) users' personal information such as age, gender, country, cognitive structure, and also computer experience and (2) user interface elements. More than 2,500 participants from 120 different countries throughout the world completed the survey. Results were analyzed using cross tables. Findings of the analysis show that there is a relationship between users' characteristics and users' interface preferences. In the presence of this relationship, an artificial neural network model is developed for the estimation of the interface preferences based on the user characteristics.