As the GUEST of 06 April 2015 and 14 August 2016, as well as Jean Hess Keller, recall, some quick searching on newspapers.com finds several hits in the Baltimore area, first at Gwynns Falls Junior High (in 1962). He remained in the area playing with St. Paul's episcopal church until at least 1968, however, there is a missing spot in the news record from 1969-1970 (inclusive) where he drops out of the public record. In 1971, he began working as a musician and composer for The Organic Theater Company, out of Chicago.

The first evidence of his involvement with the group was with Stuart Gordon's adaptation of Candide; a light-hearted, 'collegiate-humor' version that was widely panned for its protracted nature and light but unremarkable wit, but did have its proponents. The introductory scene apparently featured a troupe in clown's costume taking the stage and an audience-participation bit where balloons were released into the theater. Reviewer William Glover said the show was "performed to improbable music by Jonathan Pearthree" -- whatever that means.

After another 2 year hiatus, he reappears in public under another Stuart Gordon-led reinterpretation of a classic, Huck Finn. This one was released in 2 parts, once again by the Organic Theater Company, debuted in late 1975. This production was apparently markedly true-to-form (as opposed to the usual sanitization of the play), and for the work Pearthree created a "vivid" and "especially good" soundtrack. It re-ran as a single 3-hour setting a decade later, in 1985.

Pearthree was later called "the company's favorite composer" in a 1978 review of Night Feast, a reimagined telling of the Beowulf story. That set's score was said to be "marvelously eerie." However, his work a year later with the group's adaptation of "The Little Sister" was panned as "disastrously obtrusive."

By 1983, he was working at a Chicago record store (Rose Records, on S. Wabash Ave), where he was recalled as a particularly knowledgeable and dutiful clerk. However, he drops off the map in 1985.

As best as I can find, his full name is Jonathan Giles Pearthree. Born February 1948 to Walter and Verna Harvey Pearthree. As far as I've found, he is not presently deceased.