“Parade,” the latest book in Rachel Cusk’s long and celebrated career, is the kind of novel certain readers will embrace as speaking powerfully to their concerns in an enriching and stimulating way, and certain readers will want to throw across the room. I really don’t think she’d have it any other way. If you’d like to read a serious, challenging, cerebral novel of ideas, which doubles as an exegesis on the relationship of art to reality and (often, but not always) the female condition, then you’ll eat “Parade” up. If, on the other hand, you come looking for humor, narrative arcs, fantasy, or even character, you’ll be rather out of luck—Cusk alternately has no interest in these things or is quite purposefully doing something else.