Michelangelo is known for masterpieces like the Sistine Chapel and the statue of David, but most people probably don't know that he actually got his start in forgery. The great artist began his career as a forger of ancient Roman sculptures, art scholar Noah Charney tells Fresh Air's Dave Davies. 

By the time Michelangelo's forgery was revealed, the Renaissance master was famous in his own right. But many other artistic forgers continue to copy the work of past artists in the hopes of passing their creations off as authentic. 

The art industry, says Charney, is a "multibillion-dollar-a-year legitimate industry that is so opaque you can't quite understand why anyone participates in it." In his new book, The Art of Forgery, Charney traces a tradition of fakes and forgeries that dates back to the Renaissance. 

In many instances, forgery is a question of economics; a forgery that is authenticated may be worth millions of dollars. But Charney says that many other art forgers are doing it as a "sort of passive aggressive revenge" against an art world that was not interested in their original work — but was too dim to tell forgeries from true masterpieces. 

Charney adds that the business practices of the art world provide a "fertile ground" for criminals: "You do not necessarily know who the seller is when you're buying a work of art. You might have to send cash to anonymous Swiss bank account. You may or may not get certificates of authenticity or any paperwork attributing to the authentic nature of the work in question. You may not be certain the seller actually owns the work. You might have gentlemen's agreements and handshakes rather than contracts — and this is normal in the legitimate art world."