In this landmark book, the originator and pioneering researcher into Acceptance and Commitment Therapy (ACT) lays out the psychological flexibility skills that make it one of the most powerful approaches research has yet to offer. Beginning with the epiphany Steven Hayes had during a panic attack, this book is a powerful narrative of scientific discovery filled with moving stories as well as advice for how we can put flexibility skills to work immediately. Science shows that these skills are useful in virtually every area--mental health (anxiety, depression, substance abuse, eating disorders, PTSD); physical health (chronic pain, dealing with diabetes, facing cancer); social processes (relationship issues, prejudice, stigma, domestic violence); and performance (sports, business, diet, exercise). Hayes demonstrates how allowing ourselves to feel fully and think freely moves us toward commitment to what truly matters to us. Finally, we can live lives that reflect the qualities we choose.