"What treasures of knowledge we cluster around." That This is a collection in three pieces. "Disappearance Approach," an essay about Howe's husband's sudden death--"land of darkness or darkness itself you shadow mouth"--begins the book with paintings by Poussin, an autopsy, Sarah Edwards and her sister-in-law Hannah, phantoms, and elusive remnants. "Frolic Architecture," the second section--inspired by visits to the vast 18th-century Jonathan Edwards archives at the Beinecke and accompanied by six photograms by James Welling--presents hauntingly lovely, oblique type-collages of Hannah Edwards Wetmore's diary entries that Howe (with scissors, "invisible" Scotch Tape, and a Canon copier) has twisted, flattened, and snipped into inscapes of force. The final section, "That This," delivers beautiful short squares of verse that might look at home in a hymnal, with their orderly appearance packing startling power: That this book is a history of a shadow that is a shadow of Me mystically one in another another another to subserve.