We live in difficult times. We are facing a modern version of the four horsemen represented by unprecedented ideological, technological, social, and ecological challenges with little clarity on how to confront them as a human community.

The long-forgotten politics of exclusion are reemerging, building new narratives around the increasing fear and disillusionment of communities all over the world. The strengthening of the Islamic State in the Middle East has not only radicalized discourses of exclusion in Islamic countries, but also created fear and disdain among citizens of the West. Right-wing parties relying on racist and anti-immigration campaigns are regaining ground among voters in Europe, as well as in the U.S. This puts at risk the international community's efforts of the last 65 years, striving to create a legal framework and a holding environment to protect the rights and liberties of every human being. ¹

On the other hand, while information and technological innovations have drastically reduced human effort and shifted time allocation, they have also modified the ways we interact, communicate, and organize amongst ourselves, with as yet unforeseen repercussions. Furthermore, the rapid advance in the current development of artificial intelligence has also started to raise concerns about what will happen to human participation along productive value chains. In addition, questions have emerged regarding how this will change human labor and wage/market participation.

We do not have a clear sense of the challenges that the new global economy will pose to human communities in the future, but we are start ing to perceive its possible effects in two additional areas: the loss of natural reserves that sustain human life and the inequality gap in well-being and wealth distribution.

Climate change is no longer a hypothesis under discussion. It is posing serious threats to the livelihood of island states and coastal communities and has become a menace for the subsistence of species at sea and on land. It is certainly compromising the survival of human populations, especially the more vulnerable ones, who have few resources and capabilities to deal with its effects. While many governments are preparing their populations to face the adverse effects in the coming decades as a result of rising temperatures and drastic changes in the ecosystem, many others are not. As Jared Diamond, author of the book Collapse (2005), has warned, our civilization is on the verge of committing an environmental suicide that could make human life vanish from the Earth. If we do not address these issues today, there may not be a tomorrow. And we are still hoping for a new global leadership to surface that would reverse the effects on our planet's sustainability.

Finally, a major challenge for the global community that still lies ahead is posed by the social and economic disparities among individuals around the world. The planet today is divided between a highly developed pole, where human life is reaching toward the future, and another pole of people who aspire only to survive and are desperately looking for ways to participate in the global economy. The concentration of wealth has reached some of the worst levels seen in human history. Today, 1 percent of the global population owns more than 50 percent of the global wealth, while the other half is distributed among the remaining 99 percent, with huge concentrations in the upper deciles (^{Hardoon, 2015}). This amount of concentration of wealth is not only ethically reprehensible, but it also jeopardizes the subsistence of the capitalist system in the medium and long term.

These challenges are not to be regarded lightly. They require able and skillful leaders who can help frame the issues in such a way that people can face these problems and fully understand the risk they represent. But these challenges also require the sensitivity to understand that their nature correlates to adaptive problems and not merely to technical ones. That is, the problems are of a cognitive and epistemological social nature, which requires confronting values and our views toward them. As Professor Ronald Heifetz has stressed, problems of an adaptive nature also require an adaptive leadership approach that can take a group in the direction where all the narratives can be fully expressed, the underlying conflict can be managed, and where individuals do the work they are responsible for (^{Heifetz and Linsky, 2002}).

The adaptive leadership framework developed by Heifetz at Harvard Kennedy School of Government is an important body of ideas that shifts the attention from person-based leadership models to a more inclusive focus. Adaptive leadership confronts adaptive challenges by "addressing changes in people's priorities, beliefs, habits and loyalties." And from the former it moves into "making progress by going beyond any authoritative expertise to mobilize discovery, shedding certain entrenched ways, tolerating losses, and generating the new capacity to drive anew" (^{Heifetz, Grashow, and Linsky, 2009, p. 19}).

One of the strengths of this adaptive leadership approach involves the thorough analysis of the role that formal and informal authority play in any given system and how individuals relate to it. Whether a person is an authority figure or acts vis-à-vis one, the social and personal construction of an authority role remains highly important. This allows for the understanding of the strategies and the degree of disequilibrium that a given system can stand, and may produce the openness to challenge an authority figure that may be standing in the way of change.

Adaptive leadership becomes especially important when we realize we live in a fractured world where competing values and forces are in place, and where one isolated group cannot solve all the problems that emerge (Williams, 2015). Even the best CEO of a multinational company or president of a powerful country needs to negotiate to tackle difficult issues, but also has to build allliances; clearly he/she cannot do it on his/her own. Because adaptive leadership "wrestles with normative questions of value, purpose and process" in a global community (^{Heifetz, Grashow and Linsky, 2009: 14}), where most challenges are of a normative and not technical nature, new visions of leadership and new change agents are required.

Building on the adaptive leadership framework, in his new book, Leadership for a Fractured World, Harvard Professor Dean Williams critically sets out to understand what the characteristics of a new type of leader are, those of the "change agent." This agent has to have a set of abilities different from those of the so-called "big man leadership," which commonly corresponds to the idea of a charismatic leader eager and capable of solving group problems without disrupting people's lives.

For Williams, the new "global change agent" has to understand four key challenges: a) how to mobilize people to cross boundaries to address shared problems; b) how to change maladaptive practices to improve efficiency in the face of common threats; c) how to increase recognition among fractured groups and create bridges; and, d) how to intervene by stimulating sufficient creativity to produce breakthrough solutions (pp. XIII-XIV).

At times inspiring, at times educational, using leadership experiences and failures from a wide range of leaders in the corporate and political world, the book builds step by step a new model of leadership. A faculty member at Harvard University's Kennedy School since 1999, Professor Williams has an equally long trajectory working in the field, advising diverse stakeholders in tackling difficult challenges. He served as the chief adviser to the presidents of Madagascar, East Timor, and Nigeria. He has also trained and advised global and local NGOS and social agents on how to promote social change.

Thus, his approach is based on rigorous and thorough fieldwork, which aims to build a strong and plural diagnosis of the challenge faced. This has earned him academic recognition but also high regard from the social and private sectors. It is no coincidence, then, that the leadership challenges found in the book were shared with Professor Williams by global leaders themselves.

Their confidential narratives feed Williams's leadership model, appealing for agents who can cross cultural borders and recognize inherent cultural values that sometimes obstruct change. Separating oneself from embedded values is no easy task; therefore, an agent of change must understand when to pause and go out on the balcony, in order to have a broader view of what is going on within the system. Furthermore, this approach to leadership encourages the change agent to analyze and recognize the biases of different stakeholders, including the change agent's own, in order to understand where conflict could emerge when looking for solutions.

For the author, change is the major challenge but it requires breaking "tribal" boundaries that slow transformations in uneasy waters. In Dean Williams's conception, tribalism is the default through which people hold on to their established values and notions of reality, thus creating boundaries that prevent them from crossing over and understanding any other realm.

The value of tribalism is not unappreciated by the author, as it plays important part in terms of bonding and affiliation; it has also helps further collective identity and meaning. But identity boundaries can hinder taking advantage of the opportunity to address shared problems outside the group. Environmental damage or nuclear power deterrents are just some of the challenges that need to be address by multiple stakeholders. Therefore, a leader's role in a plural, global world is to understand when the tribal boundaries and values need to be shaken up -or even dissolved.

For Williams, boundaries will sometimes need to be redefined -or even torn down- for the group to progress. Not the kind of progress understood in modern thought, but. instead, progress defined as "making things sustainably better for all" (p. 15). Breaking down boundaries of a self-defined cultural group will depend on the presence of maladaptive practices that are keeping the group from change and solving their problems. Since what people fear the most has to do with what can they lose in the process of change, a mayor duty of any agent of change involves managing the possible losses that could come from it.

Leadership for a Fractured World forces us to look deeply into our personal and collective motivations for change. The author poses a question whose answer is not evident: what is at stake and why is change needed (p. 35)? Change is needed in most cases because the survival of the group depends on it or because the status quo is creating too much disturbance and conflict. The challenge for the group, then, is to understand that change is the necessary evil that needs to take place while people still hold power to shape the future. If not, change will come from an outside source that could completely disrupt the group's sovereignty and decision-making capacities.

The book does not stop at the why and what, but goes on to explore alternatives for how to face the challenges: How do you make a group realize that change is vital? Is it the right time to break some boundaries and to make the system more dynamic? Williams hands in his recipe: a cup of self-diagnosis and a pint of analyzing cultural narratives.

A good, efficient agent of change understands the tasks presented to the group in order to cross boundaries and does not avoid the work ahead. A leader's responsibility, in this sense, is to get the group to be responsible while doing the adaptive work needed. Among other things, diagnose the problem with multiple views, and help the groups involved to adjust their narratives, keeping in mind the importance of creating shared value.

Self-diagnosis emerges as a pillar of change, not only for the group but also for the agent promoting change. The examination of oneself allows the leader-to-be to avoid "the ugly factor" of being disrespectful or judgmental when analyzing the group's needs for change. The "ugly factor" tends to be present when the person is not able to understand that change implies having sensibility and taking care of all the people engaged in the adaptive process. Can an aspiring leader avoid the "ugly factor"? For WIlliams, the way to do this is by looking for partnerships that can walk us through the process of change: "A network of partnership increases the chances that wiser heads prevail and reduces risk of bad decisions due to bias, misinformation, misinterpretation or miscalculation" (p. 71).

Partnerships can also be an important instrument while crossing boundaries and identifying maladaptive practices. Maladaptive practices are present in all groups and can be the best indication that certain values or practices are flawed, or that the group perhaps is working in isolation. Maladaptive practices can also surface if the group is neglecting to deal with the changes that need to be made in order to avoid an overall collapse.

Political will and good leadership can help avoid collapse, but in particular they help people face reality. While reality can have its distortions, a leader's task is to be creative and engage different stakeholders with a diversity of tools: from asking good questions and applying story-telling techniques, to understanding peoples' abilities and setting personal tasks that can be completed.

In this extensive work, Williams seems to be writing down his legacy for the next generation of leaders. In his view, the leaders-to-be should aim at being adventurous; they should experiment and accept failure as a process of awareness that can further the knowledge required by the system. Defining a higher purpose can also help people develop a clear sense of direction and avoid getting lost or frustrated. But above all, leaders should have a clear idea of who they are, before setting goals to help others.

The last chapters of the book give a detailed checklist -on a more personal note- that will help anyone aiming at understanding this fascinating leadership framework. It maps out how to make a self-assessment and helps the reader understand that "leadership is not an individual burden but a collective process of creative problem solving by actively engaging with diverse perspectives" (p. 116).

From our side of the world, in a time when many voices in Mexico and Latin America are clamoring for new models of good leadership, Leadership for a Fractured World can offer an important opportunity to pause and review how the idea of leadership has been shaped by our notions of authority inserted through a long tradition of charismatic authoritarianism. An adaptive leadership process, built on Dean Williams's insights, could help deal with many of the cross-cultural issues present in Latin America, where national governments have not been able to create the holding environments for social change to take place from a plural and inclusive perspective. It could also help facilitate some of the difficult decisions that have to be made to pre-empt many of the losses that will emanate from those Four Horsemen of the Apocalypse riding close by.

This book is certainly among one of the best leadership books written to date. People interested in understanding some of the most creative insights of the leadership gurus at Harvard will be pleased to find concrete cases presented in approachable writing, yet with truly insightful depth.