He instructed Robert Silverberg in the techniques of selling large quantities of action-adventure science fiction, and collaborated with him on two novels about men from Earth disrupting a peaceful agrarian civilization on an alien planet.

[citation needed] Garrett is best known for the Lord Darcy books — the novel Too Many Magicians and two short story collections — set in an alternate world where a joint Anglo-French empire still led by a Plantagenet dynasty has survived into the twentieth century and where magic works and has been scientifically codified.

[4] An inveterate punster (defining a pun as "the odor given off by a decaying mind"), Garrett was a favorite guest at science fiction conventions and a friend to many fans, especially in Southern California.

[5] Garrett, Poul Anderson and other friends were members of the Elves', Gnomes' and Little Men's Science Fiction, Chowder, and Marching Society, centered in Berkeley, California.

a proofreader for Baen Books, recalls a quatrain that Garrett declaimed at one of the Little Men meetings: "There are thousands of laws legislators have spoken, A few the Creator sent.

Hoping that his condition was temporary, Heydron served as his caregiver for two years, but in August 1981, "for the sake of his health and [her own] sanity, [...] allowed him to be hospitalized.

The collection Takeoff Too included a poem, which the editor titled "The Egyptian Diamond", which was erroneously credited to Garrett.