Thinking Points by George Lakpoff & the RockRidge Institute

This book's subtitle is "Communicating our American Values and Vision".  It is aimed at progressives.  It discuses how conservatives have co-opted many words in our language (freedom, responsibility, etc) and changed their usage to quickly activate conservative points of view.  It also discuses how we progressives can reclaim those words and use them in ways that help promote our point of view.  There is much more to this book, and any progressive that finds themselves struggling to be really understood should give it a read.