This book, the fourth of a group of catalogues in course of publication, is a useful reference tool addressed to music students, scholars and researchers. The music of the Nani composers, one of the leading families of music makers between the 18th and 20th centuries, represents one of the biggest music collections to be found on the Maltese Islands. It forms part of the Cathedral Museum Archives and covers, practically, all musical genres in the sacred, instrumental and operatic  field.  The  "uniqueness"  of  this collection justifies the compiling of this catalogue which offers a contribution to the history of Maltese music.