Like it or not, the history of the Christian Church is the history of the Western World and MacCulloch shows there is a lot to discuss. Especially when your book puts itself forward as a global history of Christianity. MacCulloch discusses the big events in Europe but also looks at Orthodox Christianity, the Church in Africa, the Americas and Asia.
There is a lot to get through in this book but anyone interested in the subject will find a well written book that is a comprehensive look at Christianity. Just don't expect a book that you can just pick up and skim through, the subject and the size does require some effort from the reader.