This book is an observatory of the universe of the double bass player and musician's market in the 20th and 21st century, its wide-ranging repertoire, the music education institutions that offer training in the instrument and, finally, the transformations in the world of work and the vectors that have acted on them. The text addresses interpretative practices and musical repertoire, focusing on the transformations in the music market and how to adapt to them. Questions are raised about state intervention in the music market in Brazil, including the collection of royalties in mechanical performances and the granting by law to producers of sheet music. The text also discusses the importance of integrating composition and performance in the interpretation of specific repertoires and how to understand the phenomena that transform the musical repertoire for pedagogical planning. There is also a reflection on how definitions of the music market from the perspective of classical liberal philosophy can influence the social mobility of music workers.