“McPhee, the Pulitzer-prizewinning author of Annals of the Former World, performs a series of virtuosic variations on the theme of shad, including its role in history, its heroic migratory habits–a single shad can travel 10,000 miles in its lifetime–and the author’s sometimes excruciating attempts to catch the fish. “There is a God,�? he writes, gazing wistfully at his shadless line, “a God who knows what He is looking at and enjoys making decisions.�? (The emotion you’re feeling right now is shad-enfreude.)�?