This text reconstructs the historical development of Hanns Eisler’s Film Music Project from 1940 until 1947, transcribing for the first time into Spanish most of the archival materials related to this outstanding research on the relation of film and music. It also analyzes the aesthetics of the practical outcomes of the project –Eisler’s scores for the films "White Flood", "A Child Went Forth", "Regen" and "The Grapes of Wrath".

Chapter 1 deals with the exile of European artists and intellectuals into the United States, and pays special attention to the activities of three American institutions that hosted refugees (the New School, the Institute for Social Research, and the Rockefeller Foundation). Chapter 2 follows the arrival of Eisler and Adorno to New York during the years 1938 and 1939. It analyzes Eisler’s compositions for films like "The 400 Million" or "The Living Land", and studies Adorno’s participation in the Princeton Radio Research Project.

From Chapter 3 to Chapter 7 the text focuses on the Film Music Project itself. Chapter 3 deals with Eisler’s proposals for the Rockefeller Foundation, and his first score for Frontier Films’ short production "White Flood". It also follows Eisler’s trip to Hollywood with particular detail. Chapter 4 includes an analysis of Herbert Kline’s "The Forgotten Village", a film that –although it was not part of the Film Music Project as such– illustrates many of the ideas Eisler was working with during his Rockefeller research. Chapter 5 examines two of the most important results of the FMP, the scores of "A Child Went Forth" and "Regen" –focusing in the particular relation established between the music and the images. Chapter 6 explains why and how Eisler extended his research throughout 1942 in order to write compositions for some sequences of John Ford’s classical film "The Grapes of Wrath". The last Chapter is a study of the turbulent history of the theoretical outcome of the project: the book "Composing for the Films", coauthored by Eisler and Adorno.

All along the text, the author tries to demonstrate one main hypothesis: that Hanns Eisler’s Film Music Project, despite its tumultuous historical context, was an outstanding and unique research on the interaction of film and music, which also provided us with brilliant insights into the nature of cinema as a art form and mass medium.