The final episode explores how, since folk music's popularity hit a low point in the late 1970s, it has continually reinvented itself to appeal to new audiences.
Politicised folk enjoyed a renaissance during the miners' strike with punks like Billy Bragg singing about the power of unions. Artists from the 'crusty' traveller scene which followed were also re-engaged in social and political protest.
In the 1990s, second-generation folkies, like Eliza Carthy, emerged to take on the mantle of the folk traditionalists, and the BBC Radio 2 Folk Awards were launched to celebrate industry achievements.
The story is brought right up to date with the two, very different, folk scenes flourishing today:
The first is at home in the traditional folk clubs, while artists like Devendra Banhart and King Creosote belong to a neo-folk scene that harks back to some of the most exciting neo-psychedelic and pastoral folk albums of the 1960s.