Yves Klein's artistic endeavors in the 1960s continued to challenge and redefine the boundaries of art, exploring themes of immateriality, the void, and the infinite. Klein's work during this period was characterized by groundbreaking performances, conceptual art pieces, and his signature International Klein Blue (IKB). One of Klein's most iconic works from this period is "Leap into the Void" (1960), a staged photograph capturing Klein in a daring jump from a rooftop, seemingly into the void. This image, emblematic of Klein's engagement with the immaterial and his exploration of space and the void, was part of his broader theoretical framework, "Theatre of the Void." Klein envisioned a new form of theater stripped of actors, stages, and spectators, focusing instead on the conceptual and existential dimensions of space itself​ (artlead)​. Klein's fascination with dematerialization is further evident in his "Zone of Immaterial Pictorial Sensibility" series, where he sold empty space as art, documented by a receipt in exchange for gold. This act of selling the immaterial, coupled with rituals of burning the receipts and disposing of half the gold in the Seine, underscored Klein's pursuit of art that transcended physical form​ (artlead)​. The 1960s also saw Klein continue to innovate with IKB, using it in various mediums, including monochrome paintings and sculptures. Despite his untimely death in 1962, Klein's work from this brief period left a lasting impact on the art world, influencing the development of performance art, conceptual art, and the use of color as a means of conveying deep philosophical and existential questions​ (Wikipedia)​​ (Encyclopedia Britannica)​. Klein's art in the 1960s represents a pivotal moment in modern art history, where the exploration of the immaterial and the void opened new avenues for artistic expression and conceptual thinking, marking him as a visionary artist whose ideas presaged many of the developments in contemporary art.