Reddit mentions of Improvisation for the Theater: A Handbook of Teaching and Directing Techniques (Drama and Performance Studies)

>I'm going to run an improv group at an adult mental health clinic. But I never did improv.

Not to be a stick in the mud, but are you sure this is a good idea?

If you absolutely have to do this, check out this book for games. But, please, give it some thought. That maybe trying to teach something you're not proficient at, with a group of emotionally vulnerable people, where you're asking those people to do necessarily emotional work, may be a volitile situation you're not totally prepared for.

I've been doing and teaching improv for over a decade and this is the kind of thing I would sit down and have a really long, careful, think about before I did it. What I did would also be HIGHLY dependent on what the patients were in the clinic for.

I would highly suggest either Upright Citizens Brigade Comedy Improvisation Manual or any of the other books listed in the sidebar of /r/improv Or Improvisation For The Theater

The UCB manual is mostly concerned with Long-Form Improvisational Comedy, but it'll have good insight for any other kind of work.

Depending on who you ask, you can get different "tenets" of Improv. But the most basic things two I'd say are:

1.) Yes And - It is not just about literally saying yes, but about agreeing and adding information.
2.) Don't Deny - Again, this isn't about saying no, but about not denying the reality which has been created. As in, if you're in a scene where it is established that you're on normal Earth, don't just start going "Hey, I'm flying!"

Improvisation for the Theater: A Handbook of Teaching and Directing Techniques: A Handbook of Teaching and Directing Techniques by Viola Spolin

You'll make your lives a lot easier if you get a coach ASAP (even if it's just a temporary guest coach).

Player's attempting to direct each other (even for very experienced troupes) can lead to all sorts of drama down the line. I've been a part of teams where each week (or month) we rotated who was leading rehearsals. Some worked out great (the two where we all had at least a decade of performing/teaching experience and went into it with that plan) and others quickly became a dumpster fire.

My best advice while you're waiting for a coach is probably to pick up a book on improv theory or a book on on acting:

Mick Napier's - Improvise: Scene from the inside out, Bill Arnett's - The Complete Improviser, Viola Spolin's - Improvisation for the Theater, or something like Marina Caldarone's - Action: The Actor's Thesaurus are good places to start.

Then read it together outside of rehearsal and discuss the ideas in various chapters when you meet up - maybe try out a few exercises, but be wary of trying to direct each other: that's not your job, your job is to support each other on stage.

Heck, just reading a few acting books and really discussing them will put you guys leaps and bounds ahead of most improvisers.