George Bonanno, a professor of clinical psychology at Columbia University, conducted more than two decades of scientific studies on grief and trauma, which have been published in several papers in the most respected peer-reviewed journals in the field of psychology, such as "Psychological Science" and "The Journal of Abnormal Psychology". Subjects of his studies number in the several thousand and include people who have suffered losses in the U.S. and cross-cultural studies in various countries around the world, such as Israel, Bosnia-Herzegovina, and China. His subjects suffered losses through war, terrorism, deaths of children, premature deaths of spouses, sexual abuse, childhood diagnoses of AIDS, and other potentially devastating loss events or potential trauma events.