Recently at the YouTube channel History Valley, Drs. James McGrath and Mark Goodacre had a fun and friendly conversation on the existence of Q. Goodacre is known most famously for his denial of Q’s existence, positing instead that the author of Luke’s Gospel was familiar with not only the Gospel of Mark but the Gospel of Matthew as well. (I think this is the most plausible reconstruction of the relationship between Luke and the other two Synoptic Gospels.) McGrath, following what seems to be the consensus view of NT scholars at the moment, thinks that Matthew and Luke were working from a common source in addition to Mark.
McGrath admits in the conversation that this sort of redaction/source criticism is not his area of expertise. He’s done considerable work on John the Baptist (including a forthcoming volume) and the Mandaeans, a sect that traces its origins to the Baptist. McGrath also wrote an excellent book that was published recently entitled What Jesus Learned from Women. Check out my review of that book here. Nevertheless, this still made for an enlightening conversation that features two scholars who can disagree without becoming uncharitable. Take a look!
The Amateur Exegete 