On a hot summer afternoon in 1928, the leaders of the world assembled in Paris to outlaw war. Within the year, the treaty signed that day, known as the Peace Pact, had been ratified by nearly every state in the world. War, for the first time in history, had become illegal the world over. But the promise of that summer day was fleeting. Within a decade of its signing, each state that had gathered in Paris to renounce war was at war. And in the century that followed, the Peace Pact was dismissed as an act of folly and an unmistakable failure. This book argues that that understanding is inaccurate, and that the Peace Pact ushered in a sustained march toward peace that lasts to this day.
 

After four harrowing years on the Western Front, Tom Sherbourne returns to Australia and takes a job as the lighthouse keeper on Janus Rock, nearly half a day’s journey from the coast. To this isolated island, where the supply boat comes once a season, Tom brings a young, bold, and loving wife, Isabel. Years later, after two miscarriages and one stillbirth, the grieving Isabel hears a baby’s cries on the wind. A boat has washed up onshore carrying a dead man and a living baby. Tom, who keeps meticulous records and whose moral principles have withstood a horrific war, wants to report the man and infant immediately. But Isabel insists the baby is a “gift from God,” and against Tom’s judgment, they claim her as their own and name her Lucy. When she is two, Tom and Isabel return to the mainland and are reminded that there are other people in the world. Their choice has devastated one of them.