Source — Wikipedia, "Leonard Koren"

Extract

Koren trained as an artist and architect; founded WET: The Magazine of Gourmet Bathing in 1976, an avant-garde publication the article credits with influencing postmodern aesthetics; WET ceased publication in 1981, after which Koren moved to Japan.
In Japan (1983–1986) he wrote a cultural-anthropology column for a Japanese magazine before writing Wabi-Sabi for Artists, Designers, Poets & Philosophers (1994).
The article credits this book with having "helped bring the Japanese concept of wabi-sabi into Western aesthetic theory" — corroborating (independently of the English Wikipedia Wabi-sabi article, though both are Wikipedia and so not fully independent of each other) Koren's role as the term's principal English-language popularizer.

Provides no detail on the book's specific claims, sourcing, or critical reception beyond the one summary sentence quoted above.
As a Wikipedia article about Koren himself (rather than the Wabi-sabi topic article), this and the wikipedia-wabi-sabi.md source share editorial provenance (both Wikipedia) — treat their agreement on Koren's role as consistent, not as two independent corroborations.