Madonna Louise Ciccone is known universally as the 'Queen of Pop', and with career record sales topping 300 million worldwide, she is acknowledged as the biggest selling female recording artist of all time. Indeed, in Billboard's 2008 100 All-time Top Artists, she was ranked second only to the Beatles. During a 30-year career she has released 12 studio albums (plus numerous more compilations, live albums, soundtracks, remixes, EPs, and box sets). With each album she has consistently reinvented her music and image, pushing the boundaries both lyrically and in the form of elaborate and often sex-charged stage shows. But she is far more than just a 'pop star'. With a career that has encompassed not just music but books, movies, fashion and humanitarian work, she has transcended the world of pop to become a global cultural icon and a role model to millions of women. Indeed, almost every successful female recording artist of the last 30 years - from Jennifer Lopez to Rihanna and, of course, Lady Gaga - cites her as a major influence.