a time when they were still somewhat rare—Hofmann has sometimes been described as exhibiting a “straightforward male chauvinist posture.” Lee Krasner, who remained a devotee, likened some of his critiques to the back-handed praise earlier women artists often experienced (for example, “so good, you'd never know it was done by a woman!"). Sculptor Lila Katzen has related that he told her that "only men had the wings for art." Writing Hofmann's influential writing on modern art have been collected in the book Search for the Real and Other Essays (1948), which includes his discussions of his push/pull spatial theories, his reverence for nature as a source for art, his conviction that art has spiritual value, and his philosophy of art in general. In formal terms, he is especially noteworthy as a theorist of the medium who argued that "each medium of expression has its own order of being," that "color is a plastic means of creating intervals," and his awareness of a painting's frame, represented by his quote, "any line placed on the canvas is already the fifth." Hofmann believed in remaining faithful to the flatness of the canvas support, and that to suggest depth and movement in a painting an artist must create what he called "push and pull" in the image—contrasts of color, form, and texture. Hofmann held a strong conviction about the spiritual and social value of art. In 1932, he wrote: “Providing leadership by teachers and support of developing artists is a national duty, an insurance of spiritual solidarity, What we do for art, we do for ourselves and for our children and the future.” Collections and art market Hofmann's works are in the permanent collections of many major museums in the United States and throughout the world, including the: UC Berkeley Art Museum, Metropolitan Museum of Art, Solomon R. Guggenheim Museum, Whitney Museum, Museum of Modern Art, San Francisco Museum of Modern Art, Museum of Fine Arts Boston, Art Institute of Chicago, Seattle Art Museum, Baltimore Museum of Art, Museum of Fine Arts Houston, Cleveland Museum of Art, Philadelphia Museum of Art, Provincetown Art Association and Museum, Städtische Galerie im Lenbachhaus (Munich), Museu d'Art Contemporani, (Barcelona), Tate Gallery, Art Museum of West Virginia University, and the Art Gallery of Ontario (Toronto). Hofmann also designed a public work, a colorful mural located outside the entrance of the High School of Graphic Communication Arts located in the