We aim at providing an overview of the theoretical and practical issues concerning the use of earprints in forensic research. A limited account of the history of earprints in forensic investigations and their use as evidence in the court is provided. Criticism of the use of earprints for individualization is addressed and fundamental questions that require further attention are summarized. Approaches to automatic classification and matching are discussed. Finally, we summarize the results of various studies that we have performed on earprint variation.