Francis Albert "Frank" Sinatra was an American singer, actor, and producer, who was one of the most popular and influential musical artists of the 20th century. Sinatra's music has been considered timeless by many. While Sinatra never formally learned how to read sheet music, he had a fine, natural understanding of it, and he worked very hard from a young age to improve his abilities in all aspects of music. A perfectionist, renowned for his impeccable dress sense and cleanliness, he always insisted on recording live with his band. His deep blue eyes earned him the popular nickname "Ol' Blue Eyes". Sinatra led a colorful personal life, and was often involved in turbulent affairs with women.