Ciaran Carson, 'Last Night's Fun' - a poetic, impressionistic, wonderful evocation of what it is to play traditional music and bing part of the musical and social sides of sessions. My Desert Island book.

Richard Lewis, 'The Magic Spring' - a previously non-folky spends a year connecting with the folk scene and writes a generally generous and intelligent account of his excursions.

I would also suggest Rob Young's 'Electric Eden', a slightly unfocused but fascinating account of England's 'Visionary Music', folk and beyond - if it wasn't such a big book physically, considering you want it for carrying onto a plane ...