This book's most valuable points are its treatment of renormalization and non-perturbative effects in quantum field theory. Although the renormalization discussion does not get to the heart of Wilson's conceptual picture, it provides a coherent picture of the renormalization procedure without cluttering the pages with computations (a la Peskin/Schroeder).

The section on instantons (ch. 7) is almost entirely self-contained, beginning with an analysis of classical mechanics, slowly ascending to quantum field theory. A few of the earlier chapters are on topics that were hot in the 60s and 70s, so you may not want to spend the money for a book where only ~1/2 of the pages are currently relevant, especially considering the fact that it's a bit expensive.

Also, don't expect any spectacular insights into QCD, as most lectures in the book predate or are concurrent with the advent of the field.