In the aftermath of World War II, composers searched for new forms of music that could make sense of a broken world. John Cage found his solution in the I Ching, a 3,000-year-old Chinese divination text based on an arcane system of symbols. The maverick American composer—known even then for his unconventional methods, such as “preparing” the piano with metal nuts and bolts wedged between the instrument’s strings—turned what had once been used for soothsaying into a compositional strategy. A student of Buddhist philosophy, Cage had first encountered the I Ching in the 1930s, but it wasn’t until 1951—when his student Christian Wolff gave him a new English translation of the text—that he perceived its creative potential. By tossing coins and plotting the results against the I Ching’s symbological structure, he could use chance operations to determine the pitch, duration, and dynamics of the notes plotted on the stave. The goal was a musical composition completely free of the composer’s own intention. Cage’s work would eventually move into the realm of pure indeterminacy—a strategy that reached its apotheosis in 4'33'', a nominally silent piece that consists only of the incidental sounds from the venue as the performer sits, hands folded, at the keyboard. But Music of Changes is meticulously and cryptically notated, scrolling across the page at the rate of one quarter-note every 2.5 centimeters; the score is a thicket of fractions, knotty dynamics markings, unpredictable tempi, and even instructions to, say, scrape the piano’s strings with one’s fingernails. Music this challenging required a special kind of performer, and Cage found him in his friend David Tudor, to whom the piece is dedicated. Tudor, then 25, tackles it with aplomb in this 1951 recording. His fortissimo chords have the weight of falling anvils; his pianissimo passages are barely audible. For 45 minutes, the piece marches on, inscrutable and dissonant, with nary a trace of recognizable melody or repetition. Yet—and this is the performance’s brilliance—his playing is always expressive, imbuing even these most seemingly random events with passion and meaning. In a world struggling to make sense of itself, Music of Changes is an unexpected beacon of reason.