We would like to outline our opinions about the usability of biometric authentication systems. We outline the position of biometrics in the current field of computer security in the first section of our paper. The second chapter introduces a more systematic view of the process of biometric authentication — a layer model (of the biometric authentication process). The third section discusses the advantages and disadvantages of biometric authentication systems. We also propose a classification of biometric systems that would allow us to compare the biometrics systems reasonably, along similar lines to Common Criteria  or FIPS 140–1/2 . We conclude this paper with some suggestions where we would suggest to use biometric systems and where not.