Luke is inspired, literally, to write an orderly account for you, that would add to the many other attempts to compile a narrative of the things that have been accomplished among us. As someone who has followed all things closely for some time past, Luke feels obligated to weigh in with his perspective.
He does this so that you may have certainty concerning the things you have been taught. There’s a hint of concern here about those other narratives. Luke seems to be trying to fill in some gaps.
To put it bluntly, Luke realized that he knew some things that he hadn’t seen covered in the other accounts and he felt compelled to get that knowledge out there where it could do some good.
Thank God he did. Imagine the Bible without the book of Acts.
We don’t know who this book was written to. Theophilus is Greek for “lover of God.” There were real people with that name in the first century, so it may refer to one of them.
But it seems more likely that Theophilus just refers to anyone who loves God.
It’s addressed to you.