Very few of the men and women are left now who, sixty years ago, began to create in Chicago the modern techniques of improvisational theater. With the death Monday of Josephine “Jo” Raciti Forsberg, 90, the ranks of the surviving founders have grown even smaller.

The creation of concepts and rules for improvisational comedy, acting and performance—each somewhat distinct from the other—didn’t happen all at once. There was no improv big bang, but a series of events, theater troupes, experiments, workshops, cabarets and schools which sometimes flowed out of each other and sometimes not. Jo Forsberg was up to her neck in as many of them as anyone else, from The Second City co-founders Howard Alk (deceased), Paul Sills (deceased) and Bernard Sahlins (happily still among the living and still engaged in making theater), to Mike Nichols and Elaine May and Shelly Berman, to Del Close and David Shepherd and Sheldon Patinkin (also, happily, still fully engaged in Chicago theater).

Although I hadn’t seen Jo Forsberg in many years, I remember her vividly and her gifted children, too, Linnea and Eric, who were major forces in the early Off-Loop Theater scene of the 1970’s. Now with independent careers of their own in teaching (Linnea) and film (Eric), they were with her when she died Monday at Illinois Masonic Medical Center.

I’m grateful to theater critic and Columbia College teacher Albert Williams for reminding me of the details of her long career.

Jo was a member in the 1950’s of the pioneering Playwrights Theatre Club, forerunner of the Second City improv theatre, and she was an early member of Second City itself where she assisted Viola Spolin, whose pioneering work in theater games was—and is—the foundation of all contemporary improv work. Spolin, mother of Paul Sills, eventually left Chicago for the West Coast, with Forsberg taking over Spolin’s Chicago workshops. Forsberg also produced and directed the long-running Children’s Theatre at the Second City from the mid-1960s to the early 1990s, continuing to teach at Second City and later at the Players Workshop, forerunner of the Second City Training Center. Among Jo’s thousands of students over the years, according to Williams’ account, were George Wendt, Shelley Long, Harold Ramis, Bonnie Hunt, Robert Townsend and Bill Murray. Forsberg also was the aunt of the late Martin de Maat, who served for many years as artistic director of the Second City Training Center.

Linking the generation of the founders to those who followed, Forsberg invited Compass Players co-founder David Shepherd back to Chicago in the early 1980s and teamed him up with her student, improv producer Charna Halpern, paving the way for ImprovOlympic (today known as iO Chicago) which Halpern created with great improv guru and theorist Del Close. Also in the 1980s and ’90s, she owned and operated an off-Loop venue, the Theatre Shoppe on Lincoln Avenue, which produced dozens of plays and nurtured the careers of many actors, including Steve Carell and Tim Kazurinsky.

We tend to think of improvisational theater as being comedic and satiric, in the mold of The Second City or The Committee (San Francisco) or the Upright Citizens Brigade (New York, but it started here). However, the greatest improv teachers and directors, and Jo Forsberg was among them, understand that improvisation is a key to the imagination which may be applied by any actor to any given role or situation. Once dismissed as having little value, improvisation now is part of the core curriculum of any comprehensive course of acting or directing studies. Master teacher Jo Forsberg is among those who should be thanked and remembered.