Scott Walker, the pop music icon who shot to fame with the Walker Brothers in the 1960s before going on to achieve critical success in his solo career, has died at the age of 76. His record company, 4AD, made the announcement early Monday, writing that Walker was a “unique and challenging titan at the forefront of British music: audacious and questioning, he has produced works that dare to explore human vulnerability and the godless darkness encircling it.” The Walker Brothers were best known for their 1966 hit “The Sun Ain’t Gonna Shine Anymore,” before Walker quit the band to release a string of critically acclaimed solo albums: Scott, Scott 2, Scott 3, and Scott 4.