An Extant Instance of 'Q'
Is it possible that an example of 'Q' - as in, sayings of Jesus used by Luke and Matthew - has been available, but overlooked, for more than 130 years? 

These videos are a studio version of a paper presented at SIIBS, University of Sheffield, on Monday 13th April, 2015. The print version of this paper is published in New Testament Studies.
Video 1/4: The Q Factor [7 minutes]
The idea that Matthew and Luke used a, now lost, collection of Jesus' sayings has been popular with many Gospels scholars for more than a century. The commonly conceived shape of this Q document is, however, based on two fundamental mistakes (cf. companion paper - summarised in this video). When these mistakes are corrected, however, a very different understanding of 'Q' emerges ... and with it the possibility that examples may, after all, be extant. 
Video 2/4: Prime Suspect [8 minutes]
The Didache includes a group of sayings with properties that make it a prime suspect for the role of an extant instance of 'Q' - as in, sayings of Jesus used by Luke and Matthew. Scholars have, however, generally assumed that the Didache could not have been a source for the gospels. This video challenges that assumption.
Video 3/4: When Luke met Didache [12 mins]
The Didache's opening chapter includes sayings that have been roughly juxtaposed. These same sayings reappear - now worked together into a continuous whole - in Luke. This suggests that Luke knew and rationalised Didache 1.2-5a. 
Video 4/4: Didache, Luke and Matthew Too [9 minutes]
Why does Matthew deviate from Luke in passages like 'On Retaliation and Love of Enemies'? This video shows the remarkable correlation between Didache 1.2-5a and the places where Matthew deviates from the text of Luke. This suggests that Matthew conflated the Luke and Didache 1.2-5a together. This means, in short, that both Luke and Matthew made direct use of this group of sayings in the Didache ... and so an extant instance of 'Q' is identified. This is a conclusion with far-reaching implications for the study of the Gospels and Christian origins.
Related pages:
The Didache: What lies beneath? - videos seeking to uncover the original form of the Didache.
Texts - a downloadable text of the Original Didache/Apostolic Decree
The Didache: Key to the Acts-Galatians Conundrum - a video version of a paper presented at the British New Testament Conference, 2017 - which begins to explore the possibility that the Original Didache is the full Apostolic Decree of 48CE.
Further information about the Didache.
Please post questions and comments arising from the videos here.
Recommended Greek/English text of the Didache: 
Michael W Holmes, The Apostolic Fathers, (Baker Academic, 2007)