I find the many written works of the renowned psychologist Albert Ellis, PhD, to be very helpful to clients. His work is written for both clinicians and clients. His work is compelling, in most bookstores, and also available here:
For those clinicians seeking training on mental health advocacy of immigrants, refugees, and victims of torture I suggest Counseling Refugees: A Psychosocial Approach to Innovative Multicultural Interventions by Fred Bemak and Rita Chi-Ying Chung.
For those clinicians and clients interested in increasing their emotional regulation skills particularly with anxiety disorders and PTSD, I recommend reading about contemplative psychology and meditation practices. I am particularly influenced by Buddhist psychology in this area and the practical skills taught by Jack Kornfeld, PhD. A great place to start is The Wise Heart: A Guide to the Universal Teachings of Buddhist Psychology by Jack Kornfeld.