Strange that no one has so far mentioned all the crossover between jazz and folk that has been going on for 50 years or more: Davey Graham playing Grooveyard (Carl Perkins) and Better Git It Into Your Soul (Mingues); Danny Thompson playing Haitian Fight Song (Mingus); John Renbourn playing among others Little Niles; David Grisman jamming with Sephan Grappelli and of course Ewan MacColl bringing in the "the Dirty Bopper" to add a sweet blues sound to Dirty Old Town.