Imagine a therapy so hard to classify that it has been described as an ‘existential humanistic cognitive behaviour therapy’. Acceptance and Commitment Therapy, or ACT, is an innovative and creative mindfulness-based therapy, firmly based in the tradition of empirical science, yet with a major emphasis on values, acceptance, compassion and living in the present moment. Created in the early 1980s by US psychologist Steven C Hayes, ACT utilises an eclectic mix of metaphor, paradox, and mindfulness skills, along with a wide range of experiential exercises and values-guided behavioural interventions. It has proven effective with a wide range of conditions including social anxiety, depression, obsessive-compulsive disorder, schizophrenia, borderline personality disorder , workplace stress , chronic pain , drug-refractory epilepsy, weight control, smoking cessation, and self-management of diabetes.