Peace and Conflict Studies (PCS) is an inter- and multidisciplinary field with the principle aim to understand why conflicts emerge and how they develop over time in order to create less violent and more peaceful societies. The field is considered to be a discipline of social sciences, but in reality, peace research goes way beyond, as for example technology and environmental issues can have an impact on how individuals and societies interact with each other. The complex nature of conflicts is a challenge for researchers, and thus it is difficult to adopt a holistic approach and develop a universal theory to describe conflicts. Unfortunately, there are not only methodological difficulties, peace itself is a difficult word to comprehend: what do we understand by it, and consequently what do we want to achieve by peace research?
Traditionally peace means the absence of war and direct violence. It seems that throughout human history large-scale direct violence is a recurring phenomenon, which mostly takes form in violent clashes between groups of people. Although it might appear that wars have dominated human history so far, they are activities that the involved parties rarely enjoy, especially those who have to fight or directly suffer (by) the consequences. As a result, peace has always been more favourable, and it is a state that participants usually seek for. There are countless ceasefire and peace agreements, and many scholars addressed the nature of conflicts already in ancient times.
Due to advancements in technology, weapons have become more lethal and casualties sharply increased during the 20th century. As a consequence, over the century there had been an increased need to research conflicts and the preconditions of peace, thus the field was born. Now we have a broader understanding of peace, and the field aims not only to eliminate direct violence but all other forms of violence as well (structural and cultural), which often precede and are the root causes of the direct form. As mentioned before, PCS is a highly diverse and complicated field but there are quite a few books and studies which give a general outline. If you are completely new to the area we would recommend to start with Peace: A Very Short Introduction. You can get it for a few pounds on Amazon, and read it in a few hours. The next step would be one of the more comprehensive works listed below.
Christie, D.J. et al. (2000) Peace, Conflict and Violence: Peace Psychology for the 21st Century. Englewood Cliffs, New Jersey: Prentice-Hall. (Open Access)
Gleditsch, N.P. (2014) Peace research – Just the study of war? Journal of Peace Research, 51 (2), 145-158. (SAGE Journals)
Pettersson, T. and Wallensteen, P. (2015) Armed conflicts, 1946–2014. Journal of Peace Research, 52 (4), 536-550. (SAGE Journals)
Concentrating on methodology
Schrodt, P. A. (2014) Seven Deadly Sins of Contemporary Quantitative Political Analysis. Journal of Peace Research, Vol. 51 (2), 287–300. (SAGE Journals)
Smith, R. P. (1998) Quantitative Methods in Peace Research. Journal of Peace Research, 35 (4), 419-427. (SAGE Journals)
Baker, S. and Edwards, R. (2013) How Many Qualitative Interviews is Enough? London: National Centre for Research Methods. (Open Access)