Indeed Gellner criticizes "linguistic philosophy" in this book, but this designates a very specific philosophical school: the 1950's Oxford school of "language games" and "ordinary language" inspired by the late writings of Wittgenstein. So this is NOT an attack on the branch we call "philosophy of language" today, as I assumed when I bought it.

The school of linguistic philosophy that Gellner attacks is now more or less defunct in the form that he presents it, but that doesn't necessarily make this book outdated. Many forms of pseudo-philosophy (postmodernism, for example) are still prevalent and much of what Gellner says can be readily applied to any anti-rational doctrines.

And certainly the book is worth reading just for entertainment as well. Few modern philosophy writers can match Gellner's combination of intelligence and humour. The only negative is that the book is a bit too long, so there's some unnecessary repetition towards the end.