Fibonacci "Golden Ratio" of 1.6180339887498949

[nightstocker]

Fibonacci's Mathematical Books
Leonardo of Pisa wrote 5 mathematical works, 4 as books and one preserved as a letter:
Liber Abbaci, 1202 but revised in 1228.
meaning The Book of the Abacus (or The Book of Calcuating). One of the problems in this book was the problem about the rabbits in a field which introduced the series 1, 2, 3, 5, 8, ... . It was much later (around 1870) that Lucas named this series of numbers after Fibonacci.
Practica geometriae, 1220.
A book on geometry.
Flos, 1225
Liber quadratorum, 1225
The Book of Squares, his largest book.
It was translated into English by L E Sigler and published as The Book of Squares in 1987, Academic Press. Another article about this book:
Leonardo of Pisa and his Liber Quadratorum by R B McClenon in American Mathematical Monthly vol 26, pages 1-8.
A letter to Master Theodorus, around 1225.
Theodorus was a philosopher at the court of the Holy Roman Emporer Frederick II.
There is a very readable outline of the problems in the letter to Master Theodorus in:
Fibonacci's Mathematical Letter to Master Theodorus A F Horodam, Fibonacci Quarterly 1991, vol 29, pages 103-107.