The valley where it is set is located north of the San Francisco Bay Area in Sonoma County, California where Jack London was a resident; he built his ranch in Glen Ellen.

The novel The Valley of the Moon is a story of a working-class couple, Billy and Saxon Roberts, struggling laborers in Oakland at the Turn-of-the-Century, who leave city life behind and search Central and Northern California for suitable farmland to own.

She hears socialist arguments but does not definitively accept them, later meeting an old woman with an individualist view on relationships, describing how she successfully attached herself to a series of rich men.

When Billy is released from jail, Saxon insists that they leave the city and try to find their own farm, though they discover that the government no longer gives out land freely.

They discuss the wastefulness of the early American farmers, namely their habits of exhausting land and moving on, reflecting Jack London's views on sustainable agriculture.

It has been described as "road novel fifty years before Kerouac" and as reflecting London's loss of hope in socialism and growing interest in scientific farming, as well as a hymn of praise to his second wife Charmian.