Peter Jackson's film trilogy The Lord of the Rings has computerized one of the most memorable characters in J.R.R. Tolkien's classic novels. Gollum was a hobbit named Smeagol whose possession and loss of the powerful ring, which he calls his "precious," turned him into a distraught creature of animalistic drive. NPR's Liane Hansen talks to Andy Serkis, the actor who plays Gollum and Smeagol. He documented his experience in the book Gollum: How We Made Movie Magic.