Kenneth Noland's *Diameter* is a striking example of his exploration of geometric abstraction, featuring a precisely rendered circular form that commands the intimate scale of its 22-inch panel. Working in oil, Noland employs his signature Color Field approach, using the circle as a vehicle for investigating the emotional and optical relationships between hues. The work reflects his enduring interest in centering composition around a single, bold shape, allowing color itself to become the primary subject.