Everything you ever wanted to know about Classical Electro-magnetism? Probably - and a few more things besides. There's a third edition (this is the second) - I don't know what's changed.
Everything you ever wanted to know about vector calculus is probably in here, too, neatly summarised on the insides of the cover and the facing pages, which is very handy.
Have fun with Jackson and his friends, Maxwell, Bessel and Green!