Through examinations of the computational life sciences, marine biology, astrobiology, acoustics, and more, Helmreich follows scientists to the limits of these categories. Along the way, he offers critical accounts of such other-than-human entities as digital life forms, microbes, coral reefs, whales, seawater, extraterrestrials, tsunamis, seashells, and bionic cochlea. He develops a new notion of "sounding"—as investigating, fathoming, listening—to describe the form of inquiry appropriate for tracking meanings and practices of the biological, aquatic, and sonic in a time of global change and climate crisis.

Sounding the Limits of Life shows that life, water, and sound no longer mean what they once did, and that what count as their essential natures are under dynamic revision.