Richard Barrios's exploration of musicals on film arrives at a moment when the peppy cross-over genre is very much en vogue again. Franchises such as Pitch Perfect and Disney's box-office avalanche Frozen, the world's highest-grossing motion picture of 2013, have recently rekindled the cultural and economic significance of musicals for cinematic audiences. In the course of their history of almost 90 years, film musicals have enjoyed critical acclaim and commercial success in tidal cycles. Changing cultural preferences, social codes and political stances have shaped reactions to contemporary releases as well as appreciation for Hollywood's musical back catalogue more thoroughly than they have affected most other forms of American cultural production. After all, as Barrios has observed, ‘their risks are as amplified as their budgets and soundtracks, their fiscal and aesthetic stakes are high, and they stand out as much when they fail as when they succeed’ (p. 156). In response to their fluctuating significance and popularity, Barrios sets out to clarify (as the volume's slightly defensive subtitle puts it) Why Movie Musicals Matter.

Barrios, whose prime publication A Song in the Dark (Reference Barrios1995) investigated the rise of musicals for the silver screen during the Roaring Twenties, is beyond doubt an expert on the subject. With an interdisciplinary background in film studies, music history and literature, he is also academically equipped to examine a medium that is so complex in content and form. Dangerous Rhythm succeeds in explaining how a genuinely cross-media art form has swayed generations of theatre, film and music audiences outside their respective comfort zones against the backdrop of the constantly evolving show business. Approaching film musicals as a prime example that light entertainment may be particularly hard to create, Barrios's book documents how their recruitment of talent and expertise from multiple artistic spheres required them to work as well-oiled machines of numerous parts. At the same time, the volume illustrates how musicals have pushed and utilised technological progress in the world of entertainment from the arrival of feature-length sound film with Al Jolson as The Jazz Singer in 1927 to the marketing of 2012′s Les Misérables as the first musical extravaganza with fully live recorded singing performances by Hollywood stars. Discussing musicals as cultural artefacts that encapsulate the zeitgeist of their respective periods in sound and image, Barrios's account demonstrates that they have a long track record of getting away with more subversion and frivolity than any other commodity in mainstream entertainment. Devoting adequate attention to aspects of production, distribution and consumption, Dangerous Rhythm addresses an impressive range of issues in the span of 240 pages.

While it achieves a solid amount of comprehensiveness, the volume may not quite enamour all academic readers for its occasional lack of analytical rigour and argumentative profundity. Supporting its discussion of a large variety of facets with a sheer wealth of examples, Dangerous Rhythm attempts to ascertain the significance of film musicals in breadth rather than depth. As the evolution of the medium is certainly eventful and rich in contradictions, the quantity of Barrios's observations represents, in the book's best moments, a quality in itself. Yet the approach of exhaustingly sequencing case discussions works better in some chapters – for instance those on animated works and on the challenges of established film-makers to adapt to the genre – than it does in the respective sections on music, race and gender. Vast passages of Barrios's excursion through the realm of musicals flow eloquently and entirely uninterrupted by references to primary or secondary sources of significance. For a text that probes the impact of popular cultural commodities in their respective eras, quotations from historical publications are remarkably scant. The chapter on economic dimensions of musical film-making offers a potpourri of figures for select titles rather than a coherent argument with a distinguishable bottom line. The extent of four-and-a-half pages of source notes at the end hints at the author's heavy reliance on impressions and recollections of his own. Dangerous Rhythm is panoramic in scope and rich in contrast, yet it may leave readers from several scholarly disciplines longing for closer framing and sharper focus.

For a university press publication, Dangerous Rhythm is boldly unapologetic in its biases as Barrios writes with the sweeping authority of a critical connoisseur. Especially in the parts that foreground close readings of musicals for the big screen, the text leaves little room for speculation about the author's distinct preferences and reservations. In these moments, subject-specific analysis yields too effortlessly to qualitative assessments of the rather nonspecific kind: Performances are simply ‘fine – superb, really’ (p. 91) at times or even ‘to die for’ (p. 47), at others, a song is ‘as good as the occasion warrants’ (p. 64), and the work of a composer passes as ‘usually competent and sometimes inspired’ (p. 199). In the tone of a feuilletonist, Barrios attests Helena Bonham Carter to have ‘a wee mouse singing voice that only a director-husband would judge sufficient’ (p. 93), and essentialises Yolanda and the Thief as ‘magnificent pastry, with meringue and sprinkles and icing piled on beguilingly without cease, while the substance beneath it all is cracked sliver of melba toast’ (p. 165). His euphuistic style is entertaining and may even harmonise with the flamboyant nature of the subject, yet his editor may have missed a few occasions to channel the torrent of words and prescribe precise conclusions for added value.

It is no overstatement to label Richard Barrios's insight into the matter encyclopaedic, and it is fair to call his passion for the subject contagious. His volume possesses the appeal to tempt even the slightest of musical-curious readers into revisiting some iconic classics or seek out obscurities from the annals of twentieth-century popular culture. Dangerous Rhythm offers a comprehensive if idiosyncratic introduction to a cultural phenomenon deserving of intensified academic inquiry for having weathered revolutions in mass entertainment for almost a century.