Lois Clary is a software engineer at General Dexterity, a San Francisco robotics company with world-changing ambitions. She codes all day and collapses at night, her human contact limited to the two brothers who run the neighborhood hole-in-the-wall from which she orders dinner every evening. Then, disaster! Visa issues. The brothers quickly close up shop. But they have one last delivery for Lois: their culture, the sourdough starter used to bake their bread. She must keep it alive, they tell her—feed it daily, play it music, and learn to bake with it.

Joining the ranks of popular science classics like The Botany of Desire and The Selfish Gene, a groundbreaking, wondrously informative, and vastly entertaining examination of the most significant revolution in biology since Darwin - a "microbe's-eye view" of the world that reveals a marvelous, radically reconceived picture of life on Earth.