Bob Libby states his purpose in writing this slim novel plainly in the prologue to his latest book — and it’s a bit startling if one thinks all priests have rock-solid faith and no doubts.

“In my own spiritual journey, I had a midlife crisis. Was the Incarnation, ‘the Word made flesh and dwelt among us,’ merely a nice idea, or did it really happen? Was Jesus for real? Was he really ‘truly human and truly divine?’”

Over more than half a century of ordained ministry in the Episcopal Church, Libby notes, his job has been to relate Scripture to human experience. He’s preached in many settings — parish ministry; as director of radio and television at the church center in New York; in schools, cruise ships and cathedrals. His published works include “The Forgiveness Book” and “Grace Happens.”

At the beginning of “What If It’s True?”, Libby settles for himself the question of whether Jesus actually existed in a few (perhaps too few) sentences, citing the biblical and historical scholarship of N.T. Wright.

He goes on to wonder about Jesus’ early life, sparsely covered in the Gospels, and especially about Luke’s account of Jesus in the temple at age 12, astonishing the elders with his questions and answers.

In seeking to draw a personal portrait of Jesus, Libby uses Scripture, some apocryphal accounts (such as the existence of Anne, Mary’s mother) and archeological discoveries such as Sepphoris, a Roman city near Nazareth where, Libby posits, Joseph may have worked as a carpenter.

The author gracefully expands the biblical accounts of Jesus’ birth and youth, placing him in the context of a family that includes grandparents and a half-brother, James. Libby imagines that James was a son from Joseph’s previous marriage that ended with the death of his wife, Sarah.

In Libby’s hands, these are ordinary people involved in an extraordinary event and entrusted with a gift from God. His portrait of the 12-year-old Jesus is particularly vivid — a normal human boy not only learning from his parents, running around with his cousin (the young John the Baptist), but also questioning and discovering his divine destiny.

At the temple, Jesus meets the great Torah scholars Hillel and Gamaliel, gathered there for the celebration of the Passover. The boy asks about the Golden Rule, about God’s laws and about how King David, a sinful man, could be beloved of God.

As the book unfolds, the reader has the sense that author Libby is both telling the tale and following it to see where it will lead. It ends with Mary recalling the Annunciation from the Angel Gabriel and a quote from Luke after the temple scene: “And Jesus grew in wisdom and stature, and in favor with God and men.”

It feels a bit unfinished, and in some books that would be a flaw. However, for “What If It’s True?”, there is also the sense that the story continues, as we know it does.