The Norton Simon Museum is known around the world as one of the most remarkable private art collections ever assembled. Over a thirty-year period 20th-century industrialist Norton Simon (1907-1993) amassed an astonishing collection of European art from the Renaissance to the 20th century and a stellar collection of South and Southeast Asian art spanning 2,000 years. Among the most celebrated works he collected are Branchini Madonna, 1427, by Giovanni di Paolo; Madonna and Child with Book, c. 1502-03, by Raphael; Still Life with Lemons, Oranges and a Rose, 1633, by Francisco de Zurbarán; Portrait of a Boy, c. 1655-60, by Rembrandt van Rijn; Mulberry Tree, 1889, by Vincent van Gogh; Little Dancer Aged Fourteen, 1878-81, by Edgar Degas; and Woman with a Book, 1932, by Pablo Picasso. Highlights from the Asian collection include the bronze sculptures Buddha Shakyamuni, c. 550, India: Bihar, Gupta period, and Shiva as King of Dance, c. 1000, India: Tamil Nadu; and the gilt bronze Indra, 13th century, Nepal.

In 1974, Norton Simon and a reorganized Board of Trustees assumed control of the Pasadena Art Museum, taking up management of its building and incorporating its important collection of 20th-century European and American art with the outstanding collections of the Norton Simon foundations. Highlights from the PAM collection include the Galka Scheyer Blue Four Collection, a body of works by artists Lyonel Feininger, Paul Klee, Alexei Jawlensky, Vasily Kandinsky and others assembled by art dealer, scholar and muse Galka Scheyer; post-war American art, particularly from Southern California-based artists including John Altoon, Larry Bell, Wallace Berman, Bruce Conner, Richard Diebenkorn, Llyn Foulkes, Sam Francis, George Herms, Robert Irwin, and Ed Ruscha; and a photography collection comprised of works by Ansel Adams, Lewis Baltz, Manuel Alvarez Bravo, Imogen Cunningham, Frederick Sommer, Edward Weston, and Minor White, among others.