Improv might be all about improvisation and creating characters, scenes and sets in the moment, but it some preparation never hurt anyone.
Let your inner nerd run free, here are some books on improv!

Ryan Miller – Take it Easy

Katy Shutte – The Improiser’s way: a longform workbook

Mick Napier  – Behind the Scenes: improvising long form

UCB Comedy Improvisation Manual

Keith Johnstone  – Impro

T.J. Jagodowski, David Pasquesi & Pam Victor – Improvisation at the Speed of Life

Bill Arnett – The Complete Improviser

Will Hines – How to Be The Greatest Improviser On Earth

Did we miss your favorite book on improv? Yes, and…
Leave your book suggestion in the comments bellow.