I enjoyed Nicholas Elder's book, Gospel Media. I reviewed it
at Amazon. This book is very informative and informs readers of the variety of gospel media practices. Mark textualizes the precedent oral traditions for proclamation. Among other things, I like his emphasis on paratexts of the Synoptic Gospels and John's colophon, which help us understand different uses of the manuscripts for different kinds of readers: εὐαγγέλιον (Mark 1:1); βίβλος (Matt 1:1); διήγησις (Luke 1:1); βιβλίον (John 20:30).