Oh Ed, Ed, Ed, Ed. You have written a magnificent tome, but I am so conflicted about it. Party Lines is more than 400 pages: a quote from Goethe at the start, a lengthy introduction, plus a glossary and an index. But we get into semantics from the beginning. What is dance music now? Practically anything with a beat that isn’t George Ezra or Sam Fender – and they’ve probably got a load of dance mixes on the go as well.