Reza Aslan's parents came to the US at the time of the Islamic revolution in Iran and he grew up nominally Moslem. He became enamored with Christianity as a teenager, eventually fell out of love, but appears to have an abiding interest in the issues. He teaches creative writing. This book, as he says,
...is an attempt to reclaim, as much as possible, the Jesus of history, the Jesus before Christianity: the politically conscious Jewish revolutionary who, two thousand years ago, walked across the Galilean countryside, gathering followers for a messianic movement with the goal of establishing the Kingdom of God but whose mission failed when, after a provocative entry into Jerusalem and a brazen attack on the Temple, he was arrested and executed by Rome for the crime of sedition. It is also about how, in the aftermath of Jesus's failure to establish God's reign on earth, his followers reinterpreted not only Jesus's mission and identity, but also the very nature and definition of the Jewish messiah.
Around the time Jesus was active, there were many Jews fomenting rebellion against the Romans who found ruling this tribe to be troublesome. To the Jews the Kingdom of God meant banishing the Romans from Jerusalem and beyond and they were expecting the arrival of a messiah to do just that. Jesus was revolting against the Jewish hierarchy as they were complicit with and benefitting from Roman rule. Some years after his death, a radical movement grew up and managed to expel the Romans from Jerusalem and for a few years they were triumphant. Rome returned and set about not merely reestablishing their power, but burning the Temple and killing as many as possible. The mass Sicarii suicide at Masada marked the end of that rebellion.
Around the time the Romans returned, Mark wrote the first of the gospels; he wrote as a Jewish follower of Christ. Paul had begun his ministry to the gentiles and his disagreement with those who thought followers of Christ must follow Jewish law, led by James and Peter, became acute. The early Christian church was eager to distance Jesus from the zealous nationalism that led to the war with Rome.
The author points out the ways the writers of the gospels wrote their stories to convince readers that Jesus was the long-awaited messiah. This was a tall order, given the expectations for the messiah. The gospels are full of references to the prophecies about Jesus, including that he would be born in Bethlehem. So the story we hear at Christmas is that Herod required that everyone return to the place of their birth for the purposes of taxation. Aslan points out that there is no historical record of such a concept, and when you think of it, well, it does seem pretty unlikely that everyone would be uprooted for the time required to register and pay taxes where they were born.
The adoption of Christianity by the Romans obviously influenced the depiction of Jesus. It was in 325 C.E. that the Romans first convened a council of bishops to settle the question of the relation of Jesus to God and eventually to decide which writings were to be a part of the Bible. One of their more interesting choices is the Book of the Revelations (see my description of Elaine Pagels' book about Revelations).
According to the New York Times review the book is not original scholarship, but is "a serious presentation of one plausible portrait of the life of Jesus of Nazareth."