It is rather incongruous that this thread should divide so clearly into pro- and anti- what Steve Roud has written in this book when the book itself is so full of the likes of "on the other hand...", "another way of interpreting this data might be...", "It could be argued that...." etc. He bends over backwards to give a balanced interpretation.
Over and over he tries to move the emphasis from the origin of folk song (which is full of pitfalls as this thread and many other discussions show) to its development and changes during transmission once it has become widely sung enough to enter the oral tradition. For one thing, that gives a much stronger basis for a evidential approach which he totally endorses.
His clarion call is for further research and for researchers to concentrate on a factual, data based approach. He disapproves strongly of assumption without proof and regrets the lack of data in key areas and calls for more detailed study.
This should appeal to everyone who is interested to bring more focus and discipline in their thinking. To my mind, that is the most radical aspect of this book. I always read Howard Jones' posts here with interest - he seems to write a lot that is balanced and sensible, but in a recent post Howard wrote, "Instinctively I agree with Jim that the 'folk' themselves must surely have been capable of creating their own songs..." and then he constructs his arguments to support this. I'm sure that I would have fully endorsed such statements in the past but after reading this book, I have a voice whispering in my ear, "...but instinct is no longer enough."