The scholarly estimate of Luke has gone through three major fashions in the last hundred years:

(a)A century ago, he was commonly regarded as unhistorical and unreliable - not nearly on the same level as serious, unprejudiced historians such as Josephus or Thucydides. Scholars believed they could find all sorts of small mistakes of fact in Luke's writing; after all, he was a doctor who didn't practise in one place, following Paul around the ancient world - a preacher, not a historian; and so he was biased, credulous and hasty in what he wrote.

(b) The work of people like W.M. Ramsay at the beginning of the twentieth century demonstrated the great care with which Luke wrote. It became obvious that he was extremely conscientious in establishing the accuracy of the historical details he employs. He came to be seen as a reliable reporter of what really happened in the origins of Christianity.

(c) With the rise of form criticism and redaction criticism, scholars began to look with greater interest at the way in which Luke shapes his material. (Luke was particularly interesting to them because he also wrote Acts - and so he's our sole first-century source on much of the history of the early church, as well as the life of Jesus.) The question of his reliability was put to one side, and scholars started asking: what view of Jesus is Luke trying to create? How was he shaping theology to propound a particular message? (The implication that goes along with much of this criticism, of course, is that Luke or his editors have altered his material to such an extent that we can't recover many of the true facts about the original Jesus.)

As a reaction to this development, evangelical Lucan scholars such as Howard Marshall and C.J. Hemer have argued that Luke was both a historian and a theologian. There is no necessary contradiction between the two.

Luke is concerned to present a reliable, trustworthy version of what genuinely happened (as he himself claims in chapter 1); but he also has a particular theological slant on it, which reflects his own interests and highlights what he saw as most important in the story of Jesus.

We should be aware of his special interests and be able to trace them through his book; because that will be good for us in two ways: first, it will help us see clearly why Luke writes his Gospel in the way he does, marshalling certain incidents into certain places, providing certain details of a story but leaving out others, altering Mark's phraseology in his own way; and second, it will help us to identify what's special, original and unique about the writing of Luke, and why we need his book alongside the other three Gospels.