Track II diplomacy refers to "non-governmental, informal and unofficial contacts and activities between private citizens or groups of individuals, sometimes called 'non-state actors'". It contrasts with track I diplomacy, which can be defined as official, governmental diplomacy that occur inside official government channels. However, track two diplomacy is not a substitute for track one diplomacy. Rather, it is there to assist official actors to manage and resolve conflicts by exploring possible solutions derived from the public view and without the requirements of formal negotiation or bargaining for advantage. In addition, the term track 1.5 diplomacy is used by some analysts to define a situation where official and non-official actors cooperate in conflict resolution.
In 1981, Joseph V. Montville, then a U.S. State Department employee, coined the phrases Track One and Track Two diplomacy in "Foreign Policy According to Freud", which appeared in Foreign Policy (Davidson & Montville, 1981). Track One diplomacy was what diplomats did—formal negotiations between nations conducted by professional diplomats. Track Two diplomacy referred to conflict resolution efforts by professional non-governmental conflict resolution practitioners and theorists. "Track Two has as its object the reduction or resolution of conflict, within a country or between countries, by lowering the anger or tension or fear that exists, through improved communication and a better understanding of each other's point of view".
The efforts of these conflict resolution professionals, generally operating through non-governmental organizations (NGOs) and universities, arose from the realization by diplomats and others that formal official government-to-government interactions were not necessarily the most effective methods for securing international cooperation or resolving differences.
Track two diplomacy is unofficial, non-structured interaction. It is always open minded, often altruistic, and ... strategically optimistic, based on best case analysis. Its underlying assumption is that actual or potential conflict can be resolved or eased by appealing to common human capabilities to respond to good will and reasonableness. Scientific and cultural exchanges are examples of track two diplomacy. The problem most political liberals fail to recognize is that reasonable and altruistic interaction with foreign countries cannot be an alternative to traditional track one diplomacy, with its official posturing and its underlying threat of the use of force. Both tracks are necessary for psychological reasons and both need each other.