"Natural History" is one of the largest single works to have survived from the Roman Empire and purports to cover the entire field of ancient knowledge, based on the best authorities available to Pliny. He claims to be the only Roman ever to have undertaken such a work. It encompasses the fields of botany, zoology, astronomy, geology, and mineralogy, as well as the exploitation of those resources. It remains a standard work for the Roman period and the advances in technology and understanding of natural phenomena at the time. His discussions of some technical advances are the only sources for those inventions, such as hushing in mining technology or the use of water mills for crushing or grinding grain. Much of what he wrote about has been confirmed by archaeology. It is virtually the only work that describes the work of artists of the time, and is a reference work for the history of art. As such, Pliny's approach to describing the work of artists was to inform Lorenzo Ghiberti in writing his commentaries and Giorgio Vasari who wrote the celebrated "Lives of the Most Excellent Painters, Sculptors, and Architects".