Mathematician:Leonardo Fibonacci

Italian mathematician also known as Leonardo of Pisa, Leonardo Pisano, Leonardo Bonacci or usually just Fibonacci.

One of the most important figures in the history of the development of mathematics.

Wrote the highly influential and important Liber Abaci in which he discussed the Hindu-Arabic number system and its practical applications.

Most famous for the Fibonacci numbers. The number sequence itself was known to Indian mathematicians as early as the 6th century, but it was Fibonacci's Liber Abaci which made them well-known throughout Europe. The name Fibonacci comes (posthumously) from filius Bonacci, that is: son of Bonacci (his father was nicknamed Bonacci, meaning good-natured or simpleton). These were the days before official surnames.

An ironic soubriquet.

Nationality
Italian

History

 * Born: c. 1170
 * Died: c. 1250

Theorems and Definitions

 * Fibonacci numbers
 * Brahmagupta-Fibonacci Identity
 * Practical Number (discussed at length in Liber Abaci)

Concepts derived from Fibonacci numbers

 * Fibonacci Polynomial
 * Fibonacci Prime
 * Fibonacci Word
 * Reciprocal Fibonacci Constant
 * Pisano Period

Books and Papers

 * 1202: Liber Abaci (Book of Abacus or Book of Calculation) which introduced the Arabic numerals to the Western world. Sometimes (possibly erroneously) called Liber Abbaci.
 * 1220: Practica Geometriae, a compendium on geometry and trigonometry.
 * 1225: Flos, solutions to problems posed by a friend of his, Johannes of Palermo.
 * 1225: Liber quadratorum (The Book of Squares) on Diophantine equations, in which in particular the Brahmagupta-Fibonacci Identity is discussed.
 * Di minor guisa, on commercial arithmetic (lost)
 * A commentary on Book X of (lost)

Also see

 * : Chapter $3$: Notations and Numbers