Liber Abaci

Leonardo of Pisa (Fibonacci) · 1202

The work that introduced the Hindu-Arabic numeral system to Europe and popularized the sequence that bears his name.

The Fibonacci sequence appears in nature and art, and that's why it attracted a numerological mystique of its own. Its origin is arithmetic: modeling the growth of a rabbit population.

Fibonacci wasn't a numerologist, but his sequence (1, 1, 2, 3, 5… each term is the sum of the previous ones) keeps reappearing in 'sacred numbers' talk. It's worth knowing it rigorously so as not to repeat its mystique without basis.