How exactly he became attached to INFO is unknown, but there is some evidence worth considering. Ron and Paul Willis created INFO; they also owned a bookstore and published a science fiction magazine, Anubis. Anubis republished Johnson’s critique of Thayer, which originally ran in the Berkeley fanzine Rhodomagnetic Digest. In a letter to Damon Knight, Johnson said that he did not know how Anubis came to reprint the article, which implies he did not know the Willis brothers—but they obviously knew him. It is possible that they approached him. (It’s worth noting that INFO Journal said that there was a “Chapter Two” of their society in San Francisco, just as there had been with Thayer’s organization—but evidence of this Chapter Two is hard to come by.)
More important, for the purpose of exploring Forteanism from the 1930s to 1960, which is my subject, Johnson wrote to INFO about a controversial issue that, according to his recollections to Damon Knight, were what got Chapter Two expelled from the Fortean Society. A description of this letter was published in INFO Journal four years after Knight’s book on Fort came out—thus, 1974.
The letter and article concerned a collection of supposed “apports”—that is to say, things which were supposed to have been teleported—collected by the Stanford family and displayed at the Stanford University Museum. These apports were the subject of an article in an early issue of Fate magazine. That story prompted a response from Stanford, which claimed no such apports existed. Johnson dismissed this as the usual damning of unconventional facts—he knew that the Stanford family had been interested in spiritualism. (It was a spiritualist the Stanford family hired to contact their dead son who had materialized the apports.) And, he had seen the display himself while he was in living in San Francisco.
It’s worth noting that the Stanford University archive has material on these apports. So they did exist.