The letter below is the first response from Roos, in which he thanks Misakian for her students' petition, and mentions that "the next step is for myself and other members of our company to read the book." He also misspells her name, an error that is fixed in later letters.
"The Outsiders" of course ultimately went into production and was released in 1983. It stars, among others, Matt Dillon, Patrick Swayze, Tom Cruise, Diane Lane, Emilio Estevez, Rob Lowe and Ralph Macchio.
The entire correspondence is fascinating, and can be read here on the Letters of Note blog.