Sol LeWitt was born in 1928 in Hartford, Connecticut, and received his BFA in 1949 from Syracuse University. In 1953 he moved to New York, where he attended what is now known as the School of Visual Arts, and from 1955 to 1956 he worked as a graphic artist for the architect I.M. Pei. In the mid-1960s, he began taking occasional teaching positions at art schools, including Cooper Union, the School of Visual Arts and New York University. His work was first publicly exhibited in 1963 at St. Mark's Church, New York.

Since 1965, LeWitt has had hundreds of solo exhibitions. His first retrospective was presented at the Gemeentemuseum in The Hague in 1970 and a major mid-career retrospective was organized by the Museum of Modem Art, New York, in 1978. His work has been featured in innumerable group exhibitions. LeWitt's pieces have been collected by some of the most prestigious museums in the world, including SFMOMA, the Museum of Modem Art, New York, the Solomon R. Guggenheim Museum, the Metropolitan Museum of Art, the Art Institute of Chicago, the Whitney Museum of American Art, the National Gallery of Art, Paris's Musée National d'Art Moderne, Tokyo Metropolitan Museum and the Tate Gallery, London.

Development of a Distinct Philosophy
Beginning in 1962, LeWitt began to make a series of geometric wall reliefs, soon moving to free-standing objects or "structures," the name he uses for all of this sculptural work. At this time, his work was closely related to that of such artists as Carl Andre, Donald Judd and Robert Morris, who were developing the movement that was dubbed Minimalism. By 1964, his structures had been simplified to open, linear forms, in which ideas could be explored in permutations and series.

In the mid-1960s, he pioneered the Conceptual art movement, emphasizing ideas for the generation of art rather than working from physical materials. LeWitt published "Paragraphs on Conceptual Art," an influential statement on Conceptualism, in a 1967 issue of Artforum and followed this with 'Sentences on Conceptual Art," which appeared in Art Language in 1969.

In "Paragraphs on Conceptual Art," LeWitt stated the importance of reduction in the artistic process: "When an artist uses a conceptual form of art, it means that all of the planning and decisions are made beforehand and the execution is a perfunctory affair. The idea becomes the machine that makes the art." His work is focused upon the ideas behind it and the proscribed rendering of form to realize a physical manifestation of those ideas.

Supporting his idea that the thought is more important than the act, LeWitt rejects the notion of art as a unique and precious object. He often uses assistants to execute the works based upon his detailed instructions. Adherence to LeWitt's system does not validate a scientific principle or insure technical perfection. For LeWitt, an idea may be mathematically or scientifically invalid, but as long as the executor follows the system established by the artist, a true expression of the idea is produced. The intent is to merely to make good art. Instructions for executing a work give way to any number of physical manifestations of an idea; some will be beautiful, some will not, but the idea maintains its integrity. LeWitt's art exists, above all, in the space between the artist's conception and the viewer's reception; it is dependent upon the viewer's sensory responses for its completion. Some instructions are simple and straightforward, and some are long and complex.

For example, LeWitt's instructions for the execution of Wall Drawing #340, 1980, mandates:

Six-part drawing. The wall is divided horizontally and vertically into six equal parts. 1st part: On red, blue horizontal parallel lines, and in the center, a circle within which are yellow vertical parallel lines; 2nd part: On yellow, red horizontal parallel lines, and in the center, a square within which are blue vertical parallel lines; 3rd part: On blue, yellow horizontal parallel lines, and in the center, a triangle within which are red vertical parallel lines; 4th part: On red, yellow horizontal parallel lines, and in the center, a rectangle within which are blue vertical parallel lines; 5th part:
On yellow, blue horizontal parallel lines, and in the center, a trapezoid within which are red vertical parallel lines; 6th part: On blue, red horizontal parallel lines, and in the center, a parallelogram within which are yellow vertical parallel lines. The horizontal lines do not enter the figures.

LeWitt's work strikes a delicate balance between perceptual and conceptual qualities; between dedication to the simplicity and order of geometry and his pursuit of visual beauty and intuitive creation; and between his authorship and anonymity regarding his work. Wall drawings, perhaps more than any other medium LeWitt uses, illustrate this inherent tension between craftsmanship and anonymity. The historical precedent of Renaissance fresco painting, which LeWitt deeply admires, is counterbalanced by the execution of his wall drawings. By using industrial materials that erase any trace of craft and employing assistants to execute his ideas, LeWitt was one of the first artists to renounce the importance of the artist's hand. However, LeWitt's desire to adhere to a system does not negate his wish to create truly beautiful wall drawings. As the artist said in the early 1980s, "I would like to produce something I would not be ashamed to show Giotto."

Four Decades of Work
In 1968, LeWitt made his first artist's book, developing an array of variations of straight lines, overdrawn in four directions. In a logical extension, LeWitt made the radical break of executing some of these drawings in large scale with pencil directly on the wall, the first of his "wall drawings," which would form the basis for his most sustained, important and richly developed work over the next thirty years. This shift also set the pattern throughout his career of moving readily back and forth between works on paper, wall drawings and structures. It is this way of working through theme and variation among media and materials that will be highlighted in the SFMOMA retrospective.

Idea, detail and execution merge in the work Incomplete Open Cubes, 1974, in which LeWitt explores all possible configurations of an incomplete cube. Each arrangement is expressed in three ways: as a three-dimensional wooden structure composed of eight-inch segments; as a schematic drawing; and a photograph of the sculpture. kits most reduced state, the cube is achieved with three segments. At its most complex, it is fashioned with 11 edges and comes closest to forming a complete cube. Between the boundaries, LeWitt illustrates each possibility of a cube-structures
with four segments, five segments and so on. He presents the elements by rank, with both the sculptures and pictures ordered from the least to most complex.

In the 1980s, LeWitt's work shifted significantly. Geometric shapes and their permutations became the dominant subject of his 1980s wall drawings, which are executed in layers of colored ink washes that create an extraordinarily varied palette of luminous tones. His works, until then linear and muted, now included three geometric shapes-circle, square and cone-and were created with a richer and warmer palette. For example, in 1982 LeWitt executed Forms Derived from a Cube, in which he depicted variations of geometric elements found within a cube. The piece signifies the beginning of a more selective and interpretive approach to his work; with an innumerable number of possible permutations of a cube, LeWitt chose to depict only 24 variations. These, in turn, at the end of the decade, inspired a new series of complex geometric, crystal-like forms, executed both as multicolored wall drawings and as structures of white painted wood that erupt from the floor.

Over the years, LeWitt repeatedly experimented with the idea of a star in different colors and configurations. His Star series exemplifies the artist's mature exploration of serialism and geometry. LeWitt's 1996 Wall Drawing #808-presented at the Bienal Internacional Sao Paulo, where LeWitt represented the United States-features an array of three- to nine-pointed stars, each centered within a black-bordered rectangular section of wall space. The artist's strict use of geometry dictates that each star is constructed from the form of a regular polygon, and each point of the star rests on the circumference of a circle. LeWitt achieves the broad range of color in each section through a process of layering, rather than mixing, his traditional four colors. In later works from the 1990s-such as Wall Drawing #879: Loopy Doopy (Black and White), 1998, which is composed of broad, lively swirls-LeWitt began to incorporate more fluid shapes and wider brushstrokes. Moving away from the strict systematic forms of his earlier work, the latest pieces have a rhythmic optical playfulness and exuberance and an almost decorative quality, often combining bright, saturated colors with alternately saturated blacks.