Madonna Louise Ciccone is an American singer, songwriter, and actress. Known as the "Queen of Pop", Madonna has been widely recognized for her continual reinvention and versatility in music production, songwriting, and visual presentation. She has pushed the boundaries of artistic expression in mainstream music while maintaining control over every aspect of her career. Her works, which incorporate social, political, sexual, and religious themes, have generated both controversy and critical acclaim. A prominent cultural figure spanning both the 20th and 21st centuries, Madonna remains one of the most "well-documented figures of the modern age", with a broad array of scholarly reviews, literature, and art works about her, as well as an academic mini subdiscipline devoted to her called Madonna studies.