I think Brendan's on to something. The picture above offers a nice comparison between Strunk and White's little volume and the one that Pullum wrote on grammar, with Rodney Huddleston.
I guess after writing 1,860 pages that "outline and illustrate the principles that govern the construction of words and sentences...without recommending or condemning particular usage choices," one might get a little testy about a 128-page pamphlet that recommends and condemns at will and has been selling nonstop since 1959.
I'm glad my department owns a copy of Pullum and Huddleston's Cambridge Grammar of the English Language. That $161.42 price tag is a bit steep for my personal budget.