The popularity of digital music has recently rapidly increased. The widespread use on computers and portable players and its availability through the Internet have modified the interaction issues from availability towards choice. The user is confronted daily with an enormous amount of music. This situation shapes the need for the development of new user interfaces to access and retrieve music that takes full advantage of the music being digital. This paper reports the results of various user tests aimed at investigating how music listeners organize and access their digital music collection. The aim of the study is to investigate novel interaction concepts to access and retrieve music from large personal collections. The outcome of these studies was an interaction concept based on the notion of similarity of music items (artists and songs). This concept was further refined and developed into a demonstrator eventually tested with users.