The book registers World War II as both background pressure and something distinct at the same time. America has not yet entered World War II when the voyage begins, but will have joined the Allies by the end of the following year. Amidst the wider global context of military tensions, Steinbeck documents the pressures of war on scientific research.

At the beginning of the book, as the crew prepares to depart, Steinbeck notes the military buildup which is happening around them. This soon vanishes, however, as their voyage distances them from news reports of what is happening in Europe, Japan, or the United States. After spending so long on the voyage, away from the news reports, Steinbeck writes that “the world and the war had become remote to [the crew]; all the immediacies of [their] usual lives had slowed up” (200). The voyage thus provides a certain degree of distance and escapism, even if the crew cannot forget the rumblings of war entirely.

Steinbeck frames science as a human endeavor that persists beyond war and even in spite of it. The book positions his Gulf work as an anchor where order can be perceived and built into a public record, even as human society descends into chaos and bloodshed. The crew persists in routines of measurement, naming, and storage because these practices yield cumulative knowledge and teachable material—a deliberate commitment to knowledge and discovery that outlasts immediate conflict. Furthermore, while Steinbeck acknowledges the presence of violence in the natural world, he draws attention to how it is a matter of survival and ecological balance, not bloodlust. For example, the fish feed and hunt until they themselves are caught and eaten by the crew, yet this cycle of violence is natural, in contrast to the brutality of the distant war.

The book is also an attempted synthesis of scientific knowledge with wartime need, exposing how governments often misunderstand or neglect knowledge even when it is in their interest to support it. After the voyage, Steinbeck and Ed Ricketts discovered that Japanese zoologists had produced extensive ecological studies of mandated Pacific islands in English, complete with “depth, tide, currents, reefs, nature of coast” (269) that would be invaluable for planning amphibious operations. Steinbeck explains that he and Ed drafted a letter to the Navy Department in Washington, explaining the material, its possible use, and how they had come upon it. They were largely ignored, however, in spite of the usefulness of the discovery. When Naval Intelligence finally visited them, the officer was blunt and accusatory. The episode shows that careful knowledge can be present, accessible, and relevant, and still be sidelined by institutional habits and suspicion.

The narrative does not convert that frustration into cynicism. It records the attempt and returns to the work of distributing specimens and finishing the written account. The implicit claim is that scientific observation should not depend on wartime utility for its justification, even when the two can be combined. It has its own integrity and timeline, and even though scientific endeavor cannot entirely evade the pressures of war, it can nevertheless outlast them.