I would like to know recommendations for the best way to prepare for Jackson's electrodynamics next Fall. I have taken Griffith's E&M as well as the usual undergraduate math (linear algebra, advanced calculus, complex variables, probability). I realize there have been some similar posts to this in the past, but I would like to try and get some new responses. I have heard that it would be excellent preparation to study Green's functions. Also, I have heard it would be best to focus on going back and reviewing Griffith's E&M intensively. Alternatively I'm sure one could spend the summer reviewing PDE's and a more general math book like Arfken. So there are a lot of different options, but unfortunately, a fairly limited amount of time (say, 2.5 months). If I were to choose to focus on one subject intensively for the summer (with say 3-4 books on that subject), what subject would people recommend? Book recommendations?