The late '80s How To Be Cool is a both a light fantasy and very much a book of its time. A group of "cool" kids find themselves up against The National Cool Board. This is the organisation that sets the trends, and controls just what it means to fit in, and it doesn't like people getting in its way. In a fit of rebellion the schoolkids set themselves up as a rival organisation, and thansk to the "coolometer" find themselves on the winning side. Of course, like most Pullman novels, nothing ends in quite the way we'd expect, but at least the status quo has been upturned and there's a measure of choice and free will.
This isn't classic material, like The Shadow In The North or The Amber Spyglass, however it is a light fun read, and one that shows something of the promise of Pullman's later works.