The Most Successful Celebrity Authors

Alicia Silverstone signing copies of her new book 'The Kind Diet' at Book Soup, West Hollywood, CA.

Madonna looks lost as she prepares to depart from Terminal 5 at Heathrow airport.

Singer Miley Cyrus attends her book signing of "Miles To Go" at The Grove's Barnes and Noble book store on March 7, 2009 in Los Angeles, California.

TV Personality Lauren Conrad attends her "LA Candy" Book Signing at Barnes and Noble, The Grove on June 16, 2009 in Los Angeles, California.

Actress Jamie Lee Curtis arrives at the premiere of 20th Century Fox's "Avatar" at the Grauman's Chinese Theatre on December 16, 2009 in Hollywood, California.

Dita Von Teese emerges with a bouquet of flowers from a two-hour long book signing at Waterstone's in Piccadilly. She returned to her hotel to be greeted by more fans, some who had even traveled from Germany. Von Teese has been touring to promote her latest book, "Dita: Striptease".

Adult film actress Jenna Jameson arrives at the 25th annual Adult Video News Awards Show at the Mandalay Bay Events Center January 12, 2008 in Las Vegas, Nevada.

Pamela Anderson curls up with a book on the beach in Malibu, CA.

Tori Spelling signs copies of her book, "Mommywood" at Barnes & Noble.

Actress Jodie Sweetin attends the Book Party for "unSweetined" at Nobu on November 17, 2009 in Los Angeles, California.

Ozzy Osbourne holds a book signing for his autobiography "I Am Ozzy" at the Eason bookstore.

Katie Price attends the signing of her new novel 'Standing Out, My Look, My Style, My Life' at Selfridges on October 21, 2009 in London, England.

Heidi and Spencer Pratt promote their new book, "How to be Famous: Our Guide to Looking the Part, Playing the Press, and Becoming a Tabloid Fixture" at a book signing in Borders Columbus Circle, NYC.

Mary-Kate Olsen (L) and Ashley Olsen (R) attend a book signing of "Influence" at Barnes & Noble at Union Square on October 28, 2008 in New York City.

Singer Leona Lewis autographs her book "Dreams" at Waterstone's booksellers in London's Piccadilly.