Readers familiar with Lia Purpura's highly praised essay collections--Increase, On Looking, and Rough Likeness--will know she's a master of observation, a writer obsessed with the interplay between humans and the things they see. The subject matter of All the Fierce Tethers is wonderfully varied, both low (muskrats, slugs, a stained quilt in a motel room) and lofty (shadows, prayer, the idea of beauty). In "Treatise Against Irony," she counters this...