Having had perfect understanding of all things. — Better, having traced (or investigated) all things from their source. The verb used is one which implies following the course of events step by step. The adverb which follows exactly answers to what we call the origines of any great movement. It goes further back than the actual beginning of the movement itself.
In order. — The word implies a distinct aim at chronological arrangement, but it does not necessarily follow, where the order in St. Luke varies from that of the other Gospels, that it is therefore the true order. In such matters the writer, who was avowedly a compiler, might well be at some disadvantage as compared with others.
Most excellent Theophilus. — The adjective is the same as that used of Felix by Tertullus (Acts 24:3), and implies at least high social position, if not official rank. The name, which means “Friend of God,” might well be taken by a Christian convert at his baptism. Nothing more can be known of the person so addressed beyond the fact that he was probably a Gentile convert who had already been partially instructed in the facts of the Gospel history.