The full life-course of a folksong is essentially unknowable. We might know the name of its author; we might have a stack of published versions available for consultation; but we will only ever get glimpses of the role of oral tradition in its perseverance. In new contexts, songs find new incarnations. In every performance a given song is presented with the opportunity to persist and proliferate, lodged in the minds of those who hear it. And, as people sing to one another, the complex network of tiny moments of cultural transference soon becomes both too vast and too transient to follow. A song might be reduced to its melody, motifs, lyrical features and basic plot structures. This helps the folklorist to recognise its relations and measure their distance from one another. When folklorists scrutinise a particular song, they pull on it like a thread and trace those connections that the nomenclature and methodology of that discipline make visible. Very quickly, however, the folklorist comes to infer a system that has no discernible beginning or end. Therefore, in a process distinguished by its boundlessness, the evidence with which the folklorist works can seem arbitrary: simple accidents of circumstance and history. When we look at a singular folksong version, we only know that there exist many more tributaries feeding into it, and many more distributaries flowing out of it, which have left no apparent trace. The little that we can know always invokes the greater part of the tradition, which lies beyond our knowledge.

Hamish Henderson (1919–2002) called this the ‘folk process’, and its presence can be felt in every aspect of his long polymath career, not only as a folklorist and folk revivalist, but as a poet, songwriter, political activist, translator, public intellectual, and latterly, as folk hero. As a folklore scholar, Henderson set out to chart this immense and immersive terrain; as a revivalist he sought to actively intervene on its behalf. He envisaged the role of the artist in society as one caught between an absolute submission to the collective tide of human experience and the need to absorb and recreate this collective force according to an individual or personal credo.