A protest (also called a remonstrance, remonstration or demonstration) is an expression of bearing witness on behalf of an express cause by words or actions with regard to particular events, policies or situations.
Problems and Purpose
Protests can take many different forms, from individual statements to mass demonstrations. Protesters may organize a protest as a way of publicly making their opinions heard in an attempt to influence public opinion or government policy, or they may undertake direct action in an attempt to directly enact desired changes themselves. Where protests are part of a systematic and peaceful campaign to achieve a particular objective, and involve the use of pressure as well as persuasion, they go beyond mere protest and may be better described as cases of civil resistance or nonviolent resistance.
Origins and Development
Participant Recruitment and Selection
How it Works: Process, Interaction, and Decision-Making
Influence, Outcomes, and Effects
Analysis and Lessons Learned
 Wikipedia Contributors, Protest, https://en.wikipedia.org/wiki/Protest
 St. John Barned-Smith, "How We Rage: This Is Not Your Parents' Protest," Current (Winter 2007): 17-25.
 Adam Roberts, Introduction, in Adam Roberts and Timothy Garton Ash (eds.), Civil Resistance and Power Politics: The Experience of Non-violent Action from Gandhi to the Present, Oxford University Press, 2009, pp. 2-3, where a more comprehensive definition of "civil resistance" may be found.
BBC - The People are Revolting - The History of Protest
Protest History or the History of Protest?