When you think of an octopus, you might be envious of its eight limbs. After all, there's a lot to be done with eight arms. But scientists are a bit more interested in something else: its skin.

With its beguiling octopus narrator, Shelby Van Pelt’s “Remarkably Bright Creatures” has notable staying power and is back on the best-seller list — a year and a half after its release. By Alexandra ...