The author of the book is undisputed:  it is Luke, the physician, who wrote the Gospel which also bears his name.  He is a historian, but one who acknowledges the power of the Holy Spirit in his writing.  In this there is wisdom, for Luke clearly is not an eyewitness of the Resurrection.  We know little enough about him, but it is most likely that he is a convert to Christianity taught by Paul.  His method in both books is plain:  he is a researcher.  He gathers the words and evidence of others to produce his book.

In one sense this is a terrible blow to the fundamentalist school of "automatic writing."  This school holds that all the books of the Bible were written by the Holy Spirit  - the nominal authors just held the pen while the Spirit moved their hands.  If so, why the careful research?  But in another sense Acts can be called the "history of the Holy Spirit."  For as the Gospels were the biography of Christ, in a sense, Acts records what the Spirit did through the church.  No book of the Bible expounds more clearly the work of the Holy Spirit.

The study seems, perhaps, overly long to some.  The world is accustomed to thirteen weeks in the quarterly, and no topic takes more.  A pity, that.  Here is a study much longer - and yet it barely touches upon the most fundamental of things.  The wells of God are deep indeed.