Insightful, witty, as exuberant as its subject matter, Dangerous Rhythm offers a fresh, revolutionary take on a uniquely American institution: the movie musical. In a book that is at once history, analysis, investigation, and meditation, noted film historian Richard Barrios takes on the entire musical spectrum, from Al Jolson and The Broadway Melody to hip-hop and Les Misérables. Over nine decades, the musical film has been a cornerstone of the entertainment world, yet its existence has been more erratic that any other type of film. Barrios delves deep into the genre, uncovering what makes it a commercially and artistically successful art form that, despite falling in and out of favor with the American public, has a firm and enduring hold on the American cultural imagination. Each chapter focuses on a core issue relating to the musical film: what does it take to make a successful musical performer? What is the relationship between film musicals and Broadway musicals? How does the rise of certain types of popular music, such as rock or rap, affect how the musical film is received? Through it all, Barrios argues definitively and irresistibly that, as the book's subtitle asserts, movie musicals matter -- yet, as the title implies, they are terribly difficult to do well. But when they are right, they transport and captivate viewers, striking deeply resonant chords of identification and wish-fulfillment, as well as or better than any other kind of movie.