Mahalia Jackson was an American gospel singer, widely considered one of the most influential vocalists of the 20th century. With a career spanning 40 years, Jackson was integral to the development and spread of gospel blues in black churches throughout the U.S. During a time when racial segregation was pervasive in American society, she met considerable and unexpected success in a recording career, selling an estimated 22 million records and performing in front of integrated and secular audiences in concert halls around the world, making her one of the best-selling gospel music artists.