This book is an excellent text for physics graduate students. It is unsuited for undergraduate use. I echo the observation of several other commenters in that the derivations are in places too abbreviated and impose a substantial burden on the reader having to fill in the blanks.
The problems range in difficulty, with the relatively easy problems not being terribly easy in the usual sense, to very difficult. Acquiring the ability to solve Jackson problems imbues you with professional level skills as an analyst. The problems one encounters as a professional engineer or applied physicist are really not much harder than difficult Jackson problems. On the other hand, even graduate students will benefit by having a more accessible secondary text for use in a graduate electromagnetism course.
The Jackson text affords excellent preparation for professional analysis, but is not ideal from a pedantic viewpoint. It should not be one's sole resource in learning graduate electromagnetism, but it is a very valuable one. 

Review: Classical Electrodynamics

Of all of the graduate-level physics books, I have heard the most horror stories about this one. Now it is my turn to see how many sleepless nights result! Read full review

Review: Classical Electrodynamics

537.6 J13c 1999 Read full review

Review: Classical Electrodynamics

The classic book that every graduate EM professor forces on their students because they had to suffer through it when they were in grad school. At the end of the day though, I am happy for that. It ... Read full review

Review: Classical Electrodynamics

This is the standard text upon which a graduate student's love of the subject will be crushed. A formidable book, with little elegance. Which is all the more tragic for the special elegance of the ... Read full review

Review: Classical Electrodynamics

The writing and explanation are acceptable but the book is almost the defacto standard so you need to tough it out. Other books are more illuminating but its hard to argue with standard notation and lots of problems. Read full review

Review: Classical Electrodynamics

I used Jackson for my graduate level advanced electrodynamics class. I was befuddled the first semester but made a good grade. Between the first and second semesters I had to study for and take the ... Read full review

Review: Classical Electrodynamics

Even though this is the standard, I could not get past the style. I prefer Griffith's, even though I am sure Jackson is much more comprehensive. Read full review

Review: Classical Electrodynamics

Famous for its questions Read full review

Review: Classical Electrodynamics

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 ... Read full review