For a small book, Yoko Ono’s new collection of instructions, “Acorn” (O/R Books: 216 pp., $16 paper), has been in the works for a long time: almost half a century.

“It’s been nearly 50 years since my book of conceptual instructions, ‘Grapefruit,’ was first published,” the 80-year-old avant-garde icon writes in a brief introduction to the project. “Some years ago, I picked up from where I left off, and wrote ‘Acorn’ for a website event. Now it’s being published in book form. I’m riding a time machine that’s going back to the old ways!”

“Grapefruit” remains among the unsung artworks of the 1960s, an encapsulation of Ono’s aesthetic in the form of aphorisms. Originally released in 1964, it predates her relationship with John Lennon, suggesting just how much the former Beatle learned from her: a sense of openness, of the universe as inherently creative, even positive, if only we imagine it as such.

“Nature itself is very positive,” Ono insists on a recent weekday morning by phone from her New York office. “When things are not positive, they die.”

Read the full review on the Los Angeles Times.