Research on psychosocial resilience has a history of almost fifty years, beginning within the context of developmental psychopathology. Pioneering scholars on individual resilience like Garmezy [1], Werner and Smith [2], Rutter [3], Masten [4], Ungar [5], and Luthar [6] recognized that among children who grow in highly adverse circumstances there is a subgroup who manage to develop well and thrive. Antonovsky [7] was among the pioneer scholars who studied resilience in adults and recognized that surviving the most horrible experiences may not result in psychopathological and dysfunctional outcomes.

The key question in the early studies on resilient children focused on what made a difference in the lives of individuals who developed behavioral and mental health problems compared to those who did not despite living under similar circumstances. This question remains the same in contemporary research on resilience of populations affected by disasters, major incidents and terrorist attacks. Similarly, the ambition to identify protective factors that are relevant for resilience in children growing up in adverse circumstances remains the same for researchers who continue seeking correlates of resilience among adults who live in communities exposed to destruction and violence. Consequently, current research priorities and resource allocation focus on promoting resilience, and developing effective preventive interventions, strategies and policies.

The recent decades of increased threat of terrorist attacks and human-made disasters have facilitated a shift in the research, theory and services related to resilience from an approach focused on deficits towards a broader understanding of resilience based on strengths and resources. In other words, the field has witnessed a broadening of interest from developmental resilience of children growing up in extremely adverse environments, to resilience-building strategies that may facilitate recovery, help restore effective functioning and ensure positive outcomes in the wake of major critical events that threaten the well-being of individuals, families, communities and nations.

This shift is also evident in the changing definition of resilience over time. For example, Garmezey [1] in 1974, considered resilient children to be those who are “invulnerable,” who despite disadvantages adapt and perform competently. More recent definitions of resilience focus on a system capacity and response, such as: “Resilience is the process of adapting well in the face of adversity, trauma, tragedy, threats or significant sources of stress” [8]. Regarding disasters, Norris and colleagues have described resilience as a positive trajectory of adaptation after disturbance, stress, or adversity [9].

Studying resilience is based on two fundamental assumptions [10]: (1) There has been a threat to an individual or a social system, and (2) Resilience of an individual or a system can be assessed only in comparison to an expected level of positive adaptation and functioning. This means that we cannot truly assess the resilience of an individual or a community unless their usual functioning has been seriously disrupted. Another important methodological issue pertains to when to assess resilience after a disruption. Based on studies of individual recovery from posttraumatic stress symptoms [11], it seems that at least one year is the minimum time to wait after a traumatic event. Assessment of community resilience may require an even longer period. Shorter assessment periods may in fact assess post-exposure coping but not necessarily resilience. In any case, operationalization and measurements based on these assumptions remain a challenge. The chapters in this volume have all considered the evidence of resilience in the aftermath of major disruption or trauma affecting groups of people.

Another challenge for fully understanding resilience is that its meaning has moved from being understood as a personality trait, to being considered a dynamic process over time [12]. The assumed trait of an individual, referred to as “resiliency” [12], has no sound empirical proof. Systems theory has been helpful in understanding resilience as a process. In fact, it is considered to be an ongoing process of positive adaptive changes to threat and adversity, enabling further positive adaptive changes. This recognizes the importance of various interactions as well as a history of previous adaptations, and opens up opportunities for interventions. In a way, resilience is a process of transactions among individual, proximal and distal social environments which set the stage on which players like personality traits, physiology and genetic-environment interaction, attitudes and beliefs, individual and collective identities, cultures and values, individual and collective experiences, connectedness and alienation, all perform at a time of threat and disruption of habitual functioning. It is the outcome of an individual's interactions with that environment that protects him or her against the overwhelming influence of risk factors [13]. Masten cautions that, among other issues, the following need to be taken into account when studying resilience: (1) It is a complex group of concepts that always requires a careful conceptual and operational definition; (2) It is neither a single trait nor a process, but rather many attributes and processes are involved; (3) There are multiple pathways to resilience [10].

The main research question in studying resilience relates to the capacities of individuals, communities and societies to withstand and recover from highly adverse and potentially traumatic events, such as a mass casualty terror attack, organized violence, an economic crisis or a disaster. More resilience implies recovering or “bouncing back” quickly after such events, successfully coping with greater stress, and being less disturbed by the same amount of stress than someone less resilient or more vulnerable [14]. However, there are limitations with such a view of resilience for it rests on the idea of “restoring conditions” or “returning to normal” after major stress, reflecting the ideal of resuming functioning as if a disruption has not occurred. However, people, communities and nations who overcome disasters or mass violence do not remain the same as before. Crises generate changes that may increase resilience to future adversities. However, studies on posttraumatic growth indicate that only a minority of people show this capacity after trauma. There are no studies regarding communities and nations that “grow” in this sense.

In the last two decades, research on resilience has widely expanded from an exclusive focus on individual resilience to the broader ecological levels of the community and society. This is due to the embracing of the social systems perspective, alongside increasing threats from terrorism and human-made disasters. The ideal research paradigm regarding trauma, violence and disasters would be to assess resilience before the onset of the critical event, and then determine patterns of relations between these assessments and the outcome criteria of subsequent mental health and functioning of the affected individuals or community [15].

During the Advanced Research Workshop entitled Resilience: Enhancing coping with crisis and terrorism, the concept of resilience was examined from different perspectives. These are reflected in the chapters of the present volume. During the workshop, a multidisciplinary group of 29 scholars met in the Upper Galilee in Israel in January 2014, to discuss and share their views on the topic of enhancing resilience to crisis and terror. The first chapters in this volume present a highly qualified overview of the theoretical foundations and the state of the art knowledge about several dimensions of understanding resilience. In the first chapter Suedfeld reviewed responses to severe stress at the individual, community and mass levels and presented evidence that affirms human strength, and opposes the assumption that traumatic-level stressors cause psychological damage to almost all who survive them. Bryant reviewed major models and evidence from a neuroscience perspective about different ways people respond to trauma. He also discussed how stress, gender and attachment processes may be moderated to foster resilience. He presented arguments for a more refined definition of resilience as long-term functioning at a high level.

Most of the other chapters correspond to two main approaches in studying resilience in the context of mass violence and terrorism. The first approach is based on a long term follow-up of people who have been exposed to adversities or potentially traumatic events, and consequential monitoring of psychological and physiological stress criteria over time. The limitations of this approach are related to known difficulties of longitudinal studies, as well as frequent loss of interest among funders and researchers beyond several months of follow-up. A recent meta-analysis on the long-term effects of disasters has revealed a paucity of studies beyond 24 months [16]. However, the unique advantage of this approach is that it enables identifying different trajectories of resilient coping which is essential from the public health perspective and for prevention interventions. Cherry and Galea present data and supportive evidence on longitudinal trajectories of resilience and discuss implications for the public health field in this volume. Such studies are very seldom but yield a wealth of new knowledge.

The second approach in the research on resilience looks at mental health and behavioral functioning among individuals who have been exposed to a critical event, seeking patterns of variables that distinguish those individuals who meet criteria for resilient coping and functioning from those who do not cope well. The limitations of this approach are typical for any post-hoc cross-sectional research design: poor control of the critical variables at pre-exposure, which is a threat to internal validity, and lack of a temporal dynamic perspective which limits the knowledge about the long-term performance of resilient individuals and communities. For practical and funding reasons, this is the most common approach in studying the effects of disasters [16]. However, over the years, such studies have provided fairly consistent knowledge. In a chapter in this volume, Kauzlaskas and Želviene looked at associations with family resilience after enduring political oppression in Lithuania.

The third approach to studying resilience uses comparative groups of people who have and who have not been exposed to a critical event. If the comparative groups are sufficiently similar and the main difference between them is the exposure, we can learn a lot from the similarities and differences in the patterns of variables indicative of resilience. The limitations of such designs are primarily related to difficulties in identifying and recruiting truly comparative groups, yet this is crucial for the internal validity of the conclusions. A unique advantage of this approach is that it enables studying resilience at the various levels of the ecological systems: the individual, family, community and society. In this volume such a study design was used by Sagy, who presented findings in which the sense of coherence served as the explanatory factor of resilience in conflict areas, both in acute and chronic situations in Israel. Shamai, Enosh, Machmali-Kievitz and Tapiro compared the resilience of groups of couples with a focus on their relationship, some of who were living in Israel either under a high and prolonged threat of missile attack or a low threat. Relations among individual, community and national resilience under perceived national security threat, and differences between Jews and Arabs in Israel are presented in the chapter by Leykin, Aharonson-Daniel and Lahad.

In comparison to individual resilience, community resilience is still an under-researched area. The concept of societal or national resilience is even less well established. However, community resilience offers the most opportunities for prevention and interventions, and this scholarship may help inform public health policies. A critical consideration of the three levels of resilience, i.e. individual, community and national, and their interrelations are presented by Kimhi in a review chapter. The theoretical model of associations among these three levels is presented, and methods for increasing overall resilience in the face of terror are suggested. In the same chapter, he critically analyzed the main approaches in the study of resilience. In a chapter on the concept of national resilience, Parmak presented a view on the relations between societal cohesion, shared culture and resilience during periods of social instability and transition. She argues that diverse ethnic and religious identities are a potential threat to the national social fabric. Development of a multidimensional tool for the assessment of community resilience through a multidisciplinary collaboration is presented by Aharonson-Daniel, Lahad, Leykin, Cohen and Goldberg. This instrument standardizes measurement and in turn enables comparisons of community resilience at different times and across different locations. Lahad and Leykin present the integrative model of coping that has become known as Basic Ph and was developed about 30 years ago, and its implications for the study of resilience.

In sum, the chapters in this book illustrate a broad landscape of the current knowledge and research topics on resilience as related to mass violence and terrorism, which is one of the growing concerns of the world today.