The Man of Numbers by Keith Devlin

Fibonacci's Arithmetic Revolution

The Man of Numbers: Fibonacci’s Arithmetic Revolution by Keith Devlin took me by complete surprise. I picked it up with only a vague sense of who Fibonacci was, but this book uncovered an unexpected revolution in the world of numbers. I didn’t expect a medieval mathematician to be behind something so transformative, but Devlin skillfully brings to life how one man’s introduction of Hindu-Arabic numerals changed the entire course of European mathematics.

What really caught me off guard was learning how deeply Europe was stuck in outdated, cumbersome Roman numerals until Fibonacci—also known as Leonardo of Pisa—introduced a far more practical system. His book, Liber Abaci, explained how these "new" numbers made arithmetic easier and more accessible for merchants, scholars, and everyday people. As someone with a casual interest in math, I found it astonishing how something as basic as the numbers we use today was once a groundbreaking, even radical, idea.

Devlin's exploration of how Fibonacci’s work wasn’t just about mathematics, but how it impacted commerce, trade, and even the Renaissance, kept me hooked. I never realized how interconnected numbers, culture, and progress were in that era. It really piqued my curiosity, especially when I learned that Fibonacci wasn’t initially recognized as the revolutionary figure he became in later centuries.

What made The Man of Numbers so enjoyable for me was the way Devlin brought history and mathematics together in such a readable, modern way. I didn’t expect to be so fascinated by the impact of something as fundamental as numbers, but this book showed me how one idea could ripple through time and change the world. Overall, it was an eye-opening and deeply satisfying read that gave me a fresh perspective on both history and math, and left me with a real sense of how much we owe to this overlooked genius.