Isleworth Mona Lisa
According to Leonardo's early biographer Giorgio Vasari, Leonardo had started to paint "Mona Lisa" in 1503, but "left it unfinished". However, a fully finished painting of a "certain Florentine lady" surfaced again in 1517, shortly before Leonardo's death and in his private possession. The latter painting almost certainly is the one that now hangs in the Louvre. Based on this contradiction, supporters of the authenticity of the "Isleworth Mona Lisa" claim it is the unfinished "Mona Lisa", made at least partially by Leonardo, and the Louvre "Mona Lisa" a later version of it, made by Leonardo for his own use.
The Smile (book)
The "Mona Lisa" 
"The Smile" refers to the woman depicted in Leonardo da Vinci's painting. Several questions surround the mysterious painting, focusing most pointedly at the debate over who the true muse was or whether she was merely an invention of da Vinci's imagination. Napoli took the most proposed muse, Lisa Gherardini and her known husband, Francesco del Giocondo, and created a story for them based on life in Florence in the late 15th Century to early 16th Century. Although it is unknown who the sitter truly was, it is known for fact that the painting was created in Florence, Italy between the years 1503-1506.