When poet and composer Jackson Mac Low began performing his work in the mid-1950s, it was met with considerable confusion and resistance. Audiences didn't know what to make of his poems; for example, "!11.6.7!4.,a biblical poem," is accompanied by two pages of reading instructions, performed by multiple people speaking simultaneously, and begins:

In /____/ /____/ wherein the /____/ /____/
/____/ /____/ eat lest they /____/ and taken /____/ /____/ the
/____/ twenty /____/ /____/ shalt waters the ark /____/ /____/ /____/

Throughout his career, Mac Low has consistently confounded the expectations of listeners and readers alike. "People are looking to poetry for an argument, a moral, a plot, and in music they're looking for the usual progression of harmonies and rhythms," Mac Low once said, explaining why audiences sometimes resist his work. "I suppose the things they expect to get aren't there and other things are."

At the center of Mac Low's project is the idea of chance. He began working with composer John Cage in 1954 with "chance operations," or methods by which a text could be transformed beyond the intent of its author. Mac Low wrote that these methods first arose "from an attempt to lessen (or even vainly to try to do away with) the hegemony of the ego of the artist in the making of the artwork."

His first chance operations came in 1955, in the form of five "biblical poems." In each poem, integers in the title signaled the number of "events" in the respective lines of the poem. An event was either a word or the "/____/" mark, which indicated a silence equal in duration to any word the reader chose. In composing the poems, Mac Low decided on the number of events in each line based on the rolls of a die. He encouraged the use of the reader's pulse rate to determine how quickly the poem would be read. In addition, if several readers were performing simultaneously, they should not be in synch—either they should read at individual tempos, or their pages should be shuffled so that they are never reading the same lines at the same time.

Other pieces involving chance operations include his play The Marrying Maiden, where the action of the play was determined by cards given to the actors at random intervals. His performance piece, Verdurous Sanguinaria, is generated by chance operations applied to twenty-six dictionaries, and his book of poems Stanzas for Iris Lezak was composed using acrostics and diastics of newspapers, magazines, scientific treatises, and works on Buddhism. More recently, Mac Low has been striving for randomness by running poems through computer algorithms.

He has applied the same principles—the use of chance, the belief in the agency of the performer, the creative use of sound and silence—to his musical compositions. His Open Secrets, an album released in 1993, contains songs that blend vocals, wind instruments, Buddhist hymns, magazine articles, the sounds (or "phonemes") in a name, computer software, foreign languages, and even growling. The instructions on the song "Milarepa Quartet" say only that the "composition may be played on any four instruments of the same kind and range." In the track "Lucas 1 to 29," performers compose their own parts based on the Lucas number sequence—1, 3, 4, 7, 11, 18, 29 (where 1+3=4, 3+4=7, and so on).

Mac Low calls these pieces "simultaneities"—works performed in groups of two or more people that involve both a structure of rules and the option of choice. In his instructions for these pieces, Mac Low stresses that each performer be both inventive and sensitive to every other performer; egoistic overpowering should never occur, and a performance should always contribute toward the total sound. The two most important rules in performing a Mac Low piece, which appear continuously throughout his work, are "Listen" and "Relate."

While these rules may enhance a performance, they also reflect Mac Low's political worldview. A longtime pacifist and anarchist, Mac Low has said his simultaneities are a microcosm of an ideal, free anarchist society. "The community made up of the performers," Mac Low said at a Bard College conference in 1999, "is a model of a society that has certain characteristics that I would like to see abound in the wider society: the individual performers exercise initiative and choice at all points during the piece, but are also...constructing an aural situation that is not merely a mixture of results of egoic impulses, but an aural construction that has a being of its own."