The Man Who Knew Infinity by Robert Kanigel — Summary & Review

Robert Kanigel’s “The Man Who Knew Infinity” is the kind of biography that sneaks up on you. It’s not just a story about a math genius; it’s about a man who was so deeply hooked on numbers that he ignored everything else, often to his own detriment. Srinivasa Ramanujan was born in 1887 in a modest South Indian town. From a young age, he saw the world through a numerical lens, scribbling formulas and theorems that no one around him could understand—and frankly, neither could he, at least not in the way Western academia expected.

What makes Ramanujan fascinating isn’t just his raw talent but how he developed it. Without formal training, he taught himself advanced mathematics, compiling notebooks filled with formulas that seemed to emerge from thin air. These weren’t just clever tricks; many of his discoveries were groundbreaking and baffled seasoned mathematicians. Yet, his obsession came at a cost. He flunked out of college because he neglected everything but math, and his family struggled to support his unconventional path.

Enter G.H. Hardy, a British mathematician at Cambridge. When Ramanujan sent Hardy a letter packed with his formulas, Hardy was both skeptical and intrigued. After some back and forth, Hardy invited Ramanujan to England. This is where the story gets messier. The cultural gap was huge. Ramanujan, a strict vegetarian from colonial India, found Cambridge’s cold climate and social atmosphere brutal. He faced subtle racism and isolation, which took a toll on his health. But despite all this, the two men collaborated on some of the most important mathematical work of the 20th century, particularly in number theory and infinite series.

Kanigel doesn’t just paint Ramanujan as a mystical genius. He shows the man’s flaws and struggles—the loneliness, the bouts of illness, and the tension between his intuitive approach and the rigorous proofs Hardy demanded. The biography also places Ramanujan’s life against the backdrop of British colonial rule, which adds layers of complexity to his story. It wasn’t just about math; it was about identity, belonging, and the clash between tradition and modernity.

If you’re worried this is a dry math lecture in disguise, don’t be. Kanigel writes with warmth and clarity, making complex ideas accessible without dumbing them down. You get a sense of the man behind the theorems, the stubbornness that sometimes bordered on recklessness, and the brilliance that still echoes in math today.

But it’s not a perfect portrait. Some readers might find the exploration of the cultural dynamics a bit simplistic. The colonial context is acknowledged but not deeply unpacked, which can feel like glossing over the thornier issues of race and power. Also, if you’re a math nerd hoping for deep dives into Ramanujan’s theorems, you might feel a little shortchanged. Kanigel keeps the math approachable but doesn’t go full technical.

Overall, “The Man Who Knew Infinity” is a fascinating look at a man who didn’t just know numbers but whose life was a complex equation of genius, culture, and human frailty. It’s a reminder that brilliance often comes wrapped in struggle, and that sometimes the biggest discoveries happen far from where you’d expect.