In this book Dirk Nolf summarizes his half a century of study on fossil and recent fish otoliths. From the beginning of his career onwards he advocated that fossil fish otoliths cannot be interpreted well without a thorough knowledge of the otoliths of living fishes. Such knowledge not only provides information about consistent features of species and families, but also about otolith variability within species, morphological changes during development, and malformations. All this information is required for proper identification and interpretation of fossil fish otoliths. In over forty-five years Dirk Nolf built up a unique collection of Recent fish otoliths; studied fishes and their otoliths in many famous museums; and travelled around to scrutinize collections and holotypes of fossil fish otoliths. Among his many publications he reissued and extended the classical work of Chaine & Duvergier on recent fish otoliths stressing the importance of knowledge about this subject (Nolf et al., 2009).