The Complete Francis of Assisi - His Life, The Complete Writings and The Little Flowers

The Complete Francis of Assisi offers the best introduction to St. Francis yet available between two covers. 

There are many editions of the writings of St. Francis, and biographies about him, but here in this volume are BOTH.  The Complete Francis of Assisi is actually a collection of three books in one.
The Little Flowers
Francis of Assisi in His Own Words: The Essential Writings 
The Road to Assisi
The Little Flowers, this classic collection of charming tales about the life of Francis of Assisi and his early companions did more to establish the legend of this man than any other work;  Francis of Assisi in His Own Words: The Essential Writings includes his letters, prayers and monastic rules -- important documents of the early Franciscan movement.
The Road to Assisi is Paul Sabatier's ground-breaking and foundational biography of the saint, first published in French in 1894 and re-issued and expanded in 2002.