"Research on the efficacy of nonpharmacological treatments for the various anxiety disorders has been ongoing for over three decades at our institutions, the Center for Anxiety and Related Disorders at Boston University and the University of California, Los Angeles, Anxiety Disorders Behavioral Research Program. Developments in the conceptualization of panic attacks and panic disorder (PD) in the 1980s and 1990s made possible significant improvements in the psychological treatment of PD and the development of panic control treatment (PCT), a treatment for panic disorder. Since then a substantial body of evidence on the efficacy of this intervention and closely related variants containing very similar components has accumulated, and it is stipulated as a first line treatment of choice in clinical practice guidelines from the American Psychiatric Association and the National Institute for Health and Care Excellence (NICE), which produces guidelines for the National Health Service in the UK (aPa, 2009; NICE, 2019). In 2013 PCT was evaluated as meeting the criteria for an Evidence Based Program by the Division of Quality and Performance Improvement of the Substance Abuse and Mental Health Services Administration (SAMHSA) of the Public Health Service in the United States. Similarly, the Society of Clinical Psychology of the American Psychological Association (1998) rated the evidence as "strong" in supporting PCT as an evidence-based intervention for panic disorder. After the first strong evidence for the efficacy of this approach began to appear (e.g. Barlow et al.

, 1989) we recognized the value of a guide outlining the treatment procedures. Hence, the Mastery of Your Anxiety and Panic: Workbook and Mastery of Your Anxiety and Panic: Therapist Guide were written and have now been revised. Now in its fifth edition, the revised client workbook is written in a style suitable for the clients direct use, usually under the supervision of a trained professional although it can be used in a self-help format, particularly for less severe cases"--.