Liber Abaci

Liber Abaci (1202, also spelled as Liber Abbaci) is a historic book on arithmetic by Leonardo of Pisa, known later by his nickname Fibonacci. In this work, Fibonacci introduced to Europe the Hindu-Arabic numerals, a major element of our decimal system, which he had learned by studying with Arabs while living in North Africa with his father, Guglielmo Bonaccio, who wished for him to become a merchant.

Liber Abaci was among the first Western books to describe Arabic numerals. By addressing the applications of both commercial tradesmen and mathematicians, it contributed to convincing the public of the superiority of the new numerals.

The title of Liber Abaci means "The Book of Calculation". Although it has also been translated as "The Book of the Abacus", Sigler (2002) writes that this is an error: the intent of the book is to describe methods of doing calculations without aid of an abacus, and as Ore (1948) confirms, for centuries after its publication the algorismists (followers of the style of calculation demonstrated in Liber Abaci) remained in conflict with the abacists (traditionalists who continued to use the abacus in conjunction with Roman numerals).