You may have read Guthrie's New Testament Introduction in seminary, or even perhaps in your undergraduate training. When I read such works I live for lines like this, part of Guthrie's argument that we can trust early tradition's judgment on the authorship of Luke-Acts: It will not be denied that an initial conjecture [namely, that Luke wrote Luke-Acts] may be repeated by successive witnesses until it becomes mistaken for fact, as the history of modern criticism abundantly illustrates, but...