What made you decide to write a book about the life of Jesus?
And why did you choose to focus on the Gospel of Mark rather than any of the other three gospels?
You're an author, so you'll probably laugh at this: I chose Mark because it's the shortest gospel. But because it's short, it's compressed, and it moves from incident to incident in Jesus' life very quickly. In Matthew, Luke, and John, you have these long discourses, long pieces of teaching, and they're wonderful in many cases, like the Sermon on the Mount. And they raise a lot of questions.
But if you're really just trying to get exposed to all the aspects of Jesus, in Mark you get three or four incidents: Jesus with the dying girl, Jesus with the Pharisees, Jesus with a scholar. You get so many pictures of him per chapter that very quickly you get a very full-bodied picture of who he is. Also there's a sense of immediacy: it's all in the present tense. Sometimes it says, "Immediately he did this, immediately he did that." It's pretty compelling. I always go there, to Mark, if I'm trying to introduce somebody to Jesus. It's the fastest way to give the person a picture.
There's much more, of course, at the link above.
Other helpful Tim Keller links...