Martijn Oosterbaan has devoted much of his life to studying the religious life of the inhabitants of Rio de Janeiro's favelas: beginning with a period of immersion in 2001–3, then frequent visits until a second spell of in-depth research in 2011, and again in 2014 and 2016. Throughout he has focused tightly on the religious life of their evangelical inhabitants and especially on how it has been shaped, as is alluded to in the title of his book, by daily exposure to radio and TV, to the exactions of traffickers, to the relentless blare of funk and rap, and to the preaching of evangelical pastors. Reliable ethnography in this context requires sensitive observation and resistance to sensationalism, and Oosterbaan exhibits both. For example, instead of making facile generalisations about Pentecostal preachers, he explains how pastors come in different shapes and sizes: some preach hellfire and promise eternal happiness to those who would renounce the world and accept Jesus; others promise health and wealth to those would join in the war against the forces of evil and the possession cults which do Satan's dirty work, and develop a belief in themselves; and some deftly mix politics in with their preaching and healing.

The more austere Pentecostalism preaches a form of renunciation of ‘the world’, which means resisting ties with drug trafficking (not easy), choosing and holding to stable partnerships and parenthood (also not easy), and turning away from the path of the possession cults, which leads to certain perdition. It means treating the fantasy lives depicted in telenovelas as just that – fantasy: even so-called ‘reality TV’ is fantasy. In the standard Pentecostal narrative these challenges are met by sudden illuminations, a bolt of lightning, a wake-up call or the voice of a divine being; but, as Oosterbaan explains, the experience of conversion is usually much more gradual and the involvement of those who say they belong to a church is often uneven. Nonetheless, evangelical injunctions and warnings, with their concomitant supernatural rewards and threats, are omnipresent in the low-income neighbourhoods.

Nor is Pentecostal influence limited to the religious sphere: although politics does not figure in the book's local ethnography, the description of the campaigning-cum-preaching skills of Marcos Crivella shows why he was once elected as federal Senator for Rio state, why his victory in the 2016 mayoral election with a 60 per cent vote in the run-off should have come as no surprise, and why he is surely a future presidential contender. Once again, we learn not to underestimate the Universal Church of the Kingdom of God in which Crivella is a very prominent figure and whose leader, Edir Macedo (his uncle), has presumably masterminded his rise to power.

Cognitive scientists reason that one of the explanations for the enduring force of religion is that our minds have evolved to look for human agency in explaining what we experience and observe – hence belief in the supernatural, or simply the superstitions which pepper everyday life. Pentecostal preachers tell their listeners to look everywhere for signs of the positive action of the Holy Spirit and the pernicious influence of diabolical forces. As Oosterbaan puts it, they ‘classify, incorporate and purify many “worldly” phenomena that surround people’ (p. 110). In the insecure lives of his interlocutors, marked by economic precariousness and repeatedly thrown off track by disloyal partners, wayward sons and menacing gunmen, everything in their surroundings can be taken as a sign of those forces. The forces of harm come from without, while the force for good comes from within: to follow the call of the Holy Spirit requires determination, strength of character, and not infrequently physical courage – as when women (always women) confront the men of violence with nothing but the force of their personality, translated as the inspiration of the Holy Spirit. Sometimes though, more prosaically, it just requires people to switch off the television.

Pentecostal conquest of the city's spirit has not, however, been accompanied by a conquest of its streets – and this book gives a clue to explaining why this is only an apparent paradox. In the neo-Pentecostal culture pioneered by the Universal Church, there is nuance in the separation of the world of darkness (alias ‘the world’ tout court) and the world of light. That rhetoric and the accompanying procedures of exorcism and malediction are more attuned to healing and this-worldly success: Crivella is described administering blessings on the heads of traffickers to take the devil out of their lives, and its preachers are well known for telling their listeners that they do the work of God by self-realisation. In contrast to what some might, uncharitably, call a ‘quick-fix’ version of religion, the Assemblies of God lay much more emphasis on an austere God-fearing lifestyle, although many of their congregations have also been affected by the neo-Pentecostal tsunami.

The subject of softening frontiers becomes more sensitive when Oosterbaan mentions some troubling connections, namely gangsters ‘taking up Pentecostal practices (and identities) to protect themselves against the forces that threaten them (other commandos, the police, militia etc.)’ (p. 140). But he leaves it at that. Another example of softening frontiers is music, where we learn of the absorption by ‘gospel’ (a much broader term in Brazil to cover most Pentecostal music) of funk – a genre associated with very un-evangelical habits. A comparable example of genre-crossing is in the newspaper of the Universal Church, which Oosterbaan dissects with admirable lucidity: rather than an organ of sermonising, the church has made it into a newspaper almost like any other, for example using images to focus attention on a news story and then directing the reader to an article inside the paper which spells out the moral of the story.

I was sorry that the theme of the famous, or notorious, dízimo, or tithe, was not mentioned. Maybe Oosterbaan's informants did not talk about the contributions they are expected to make to their churches, because pressure to donate both regularly and to special campaigns or causes, is extremely heavy, especially in the Universal Church, and this has gained it a bad name – although not to the point of reducing its accumulation of wealth, or the votes of its candidates, or its ability to gain ministerial office, even while its lay numbers have been falling off. Even if his interlocutors did not want to talk about the subject, that in itself would have been worthy of analysis.

Although the author does not call this an ethnography, perhaps for a reason that remains unstated here, I would nevertheless say this is an exemplary piece of ethnography, and that it marks an undoubted step forward in the interpretation of a phenomenon which remains abundantly described but continues to cry out for creative interpretation. The inclusion of violence and the media is to be applauded: others have noted their prominence, but here it is fully incorporated into the analysis. If I have any criticisms it is more of the genre of anthropological exposition than of the author himself. I sense that he feels obliged to include modish theoretical allusions when they add very little to his interpretation, as if this was a reverence owed to the profession. I also find the inclusion of extensive extracts from interviews of limited use: this may be done to demonstrate authenticity or faithfulness to his informers, but it would be more helpful to extract key words and phrases, to put readers in touch with the local culture, rather than inflict these slabs of transcribed text. In this way the ‘noise’ can be removed and readers can be made aware of the conceptual structures shaping the ‘world-view’ of informants, or maybe just their hopes and fears.