The author describes his book as ‘a response to the many historians, sociologists, theologians, atheists, agnostics and media pundits who in recent decades have declared Christianity … to be in retreat’.Hylson-Smith is an academic who writes in clear straightforward sentences. He takes issue with those who predict the demise of Christianity – ‘since 1700 Christianity has undergone its greatest period of expansion ever’ and Christians need not be despondent.Here is a vast sweep of history and geography, and a breadth of analysis – Roman Catholicism, Anglicanism, Pentecostal/Charismatic and even Evangelical. He records the revivals of the eighteenth century in Europe and America as the fount for 200 years of global mission. The main focus of the book is an analysis of twentieth century Christianity in the West, South America, Africa and Asia.He concludes that ‘there are now approximately two billion Christians in the world, about a third of the total population of the planet’ – 560m in Europe, 260m in North America, 480m in South America, 360m in Africa, and 313m in Asia – and that ‘such statistics represent a sensational globalisation of Christianity’ and make a mockery of doom-laden Western academics.But the author fails to distinguish what Christianity is in doctrinal terms – it is just assessed as a sociological movement. Therefore, although this book may challenge sceptical academics it will do little to edify evangelical Christians.We want to worship God for the spread of the true gospel of Jesus Christ (God and Christ are hardly mentioned in the book). We want to hear some doctrinal assessment of all this growth – not an implicit ecumenical agenda.In summary – interesting but not heart warming, informed but not discerning.