Start with a book of lit-crit intended for school children. End with a dystopia future of misery. What amazing development of ideas one can get.
Though, actually, Lewis points out fairly quickly that the authors didn't deliver on the lit-crit side of things. Instead, they were offering amateur philosophy, bent on debunking sentiments. And for all practical purposes, all sentiments -- including loyalty, patriotism, and the like. And what, in due consequence, results, with some considerable debunking of other techniques of reestablishing such sentiments as they like.
And the perfectly engineered, with eugenics and conditioning, future that would be the logical consequence of abandoning them all.