Leonardo da Vinci 
The Notebooks of Leonardo Da Vinci — Complete 

The great artist Leonardo da Vinci's notebooks probably started out as just a way for him to improve the quality of his paintings. He studied anatomy to portray the human body accurately. He studied plants and rocks to make them authentic for his paintings. Somewhere along the line, however, the books became more than that. They became a record of his life-long fascination with nature and his genius for invention.