Mooney Grove Park, California’s oldest county park, spans 100 acres of oak woodland surrounding a picturesque lagoon, offering peaceful walking paths, picnic areas, and historical exhibits.

The time certainly looks ripe for not one but two books on the dropping of the very first atomic bomb, on Aug. 6, 1945, with Garrett Graff’s “The Devil Reached Toward the Sky” and Iain MacGregor’s ...