What is the author's style in A History of God: The 4000-year Quest of Judaism, Christianity, and Islam by Karen Armstrong?

The History of God, as presented by Armstrong, is a more or less continuous development from Judaic religion, through the Christian era and, subsequently, through the emergence of the Muslim religion in 620 CE. Confining the subject to this single arena of religious evolution excludes analysis of other religious belief systems, which preexisted and coexisted in Europe and the Middle East. Inclusion of these other religions would provide a wider scope and help delineate the universal perspective of the emergence of the monotheistic religions.