Biography makes behemoths of individuals. Biography illustrates the Great Man Theory of History, a relic of the Victorian age. No person is that important, modern historians contend. There are forces at work, trends and trajectories that trump the roles assigned to heroes.

But if you don’t major in history, then you are likely to personalize the past. Biographies are built on a human scale, and the genre implies not merely that individuals make a difference, but that it is impossible to understand the nature of the world except through singular sensibilities.

A title such as “Master Mind: The Rise and Fall of Fritz Haber, the Nobel Laureate Who Launched the Age of Chemical Warfare” (Ecco, 314 pages, $24.95) makes just that point: Without Fritz Haber, where would we be? Well, 2 billion of us would not here, Daniel Charles contends. Haber was the first scientist to capture nitrogen from the air and turn it into liquid ammonia and other solutions and powders that have driven the agricultural revolution of the past 100 years. That nitrogen-capturing process has fertilized the earth, making the land at least four times as productive as it was before Haber invented his life-enhancing process.

Ah, but if not Haber, someone else, the historian might say. Certainly. But how soon someone else? History turns on timing. Haber, an Oppenheimer kind of scientist, had the drive and organizational skills to change fundamentally the way governments and their people do business. Knowledge is power only if you know how to use it. For better or worse, there are very, very few Fritz Habers in the history of humankind.

Haber was born a Jew in Germany. He grew up in the 1870s, just when the idea of German nationhood began to thrill a land ruled by a kaiser determined to challenge Britain and France for supremacy. Fritz found his father narrow-minded, too willing to accept the limitations put on Jews. Early on, Fritz decided not merely to assimilate but to identify himself entirely with the fortunes of the new Germany. Haber adopted the kaiser’s aspirations: “power, honor, national influence,” Mr. Charles writes. “The state’s goals were his own.”

Long before President Eisenhower warned of the dangers of a military-industrial complex, Haber was building one. He was one of the creators of chemical warfare, personally directing the “deployment of poison gas against Germany’s enemies,” Mr. Charles reports. And, as Mr. Charles points out, the nitrogen fertilizer that fructified the world was also combined in bombs like the ones used by Timothy McVeigh in Oklahoma and other terrorists around the world.

He jettisoned or suppressed anything that could be an impediment to his ambition, which was inseparable from his devotion to Germany. He never seems to have considered the political implications of his decision to make science serve the state. He converted to Christianity. He restricted his wife Clara – a promising scientist and one of the first women to compete in a male-dominated academic world – to the home.

Mr. Charles, an elegant writer who gives the lie to the idea that biography is not a historically conscious discipline, rightly focuses on one of Clara’s letters to a colleague, written in 1909 when Haber was well on his way to becoming a “great man”:

All of Fritz’s human qualities … are nearly shriveled up, and as the expression goes, he’s old before his time. On occasions, as in the days we spent in Zurich, a youthful streak still emerges, but anyone who’s around him continuously can’t escape this impression. He isn’t fair enough to look for the reason within himself, but blames me along with our social circle. And last but not least, if he weren’t kept from it, he’d ruin his health even more than is the case al ready, despite my truly “harassing” care. Everybody has a right to live their own life, but to nurture one’s “quirks” while exhibiting a supreme contempt for everyone else and the most common routines of life – I think that even a genius shouldn’t be permitted such behavior, except on a desolate island.

What do you think?

The splendid photographs in this book bear out her assessment of Haber’s physical decline. But there is real love in this letter as well as a sense of humanity that Haber rejected. Clara found herself defeated by a closed mind.

There are many ironies in Haber’s story. He invented a gas, Zyklon, which became Zyklon B, the Nazis’ preferred instrument for exterminating Jews. Many of Haber’s own relatives died in concentration camps. And, in the end, deprived by the Nazis of his institute, Haber died in disgrace in 1934.

Mr. Charles refuses to apply hindsight to Haber’s story: “During the years when Fritz Haber climbed toward fame and fortune, the Holocaust was still unimaginable, and it was not inevitable.” For all Haber’s faults, he was not a villain, his biographer emphasizes. If he lived as a modern Faust, “his defining traits – loyalty, intelligence, generosity, industry, and creativity – are as prized today as they were during his lifetime.”

If, in one sense, Haber’s story is unique – hence a biography – in another, it is representative. “His goals were conventional ones,” Mr. Charles notes: “to solve problems, prosper, and serve his country. And this is what makes the story tragic, for those goals, however familiar and defensible, led down twisting paths toward destruction.”

What can a single case prove? asks the deductive historian. Almost everything, responds the inductive biographer.