My friend Alan Hirshfeld has just published a terrific book on Michael Faraday, the early-19-century experimentalist who as much as anyone can be called the Father or the Electrical Age. Born into poverty and trained as a bookbinder, Faraday had rough going to establish himself among the pompous well-born gentlemen of the Royal Society and Royal Institution. Nevertheless, from simple but elegant experiments he forged the notion of the electric and magnetic fields -- and transformed science. Hirshfeld tells the story brilliantly.
Where did the idea of the field come from. Out of Faraday's prodigiously fertile imagination, of course, as Hirshfeld makes clear. But for an exercise in the archeology of ideas, see my previous Musing, and especially the illustrations therein.