General principles of law are essential rules whose content is very general and abstract, sometimes reducible to a maxim or a simple conception. Unlike other types of rules such as enacted law or agreements, general principles of law have not been posited according to the official sources of law. Yet, general principles of law are considered to be part of positive law, even if they are just used as subsidiary tools. They constitute necessary rules for the very functioning of the system and, as such, are inducted from the lawful reasoning of those entitled to take legal decisions in the process of applying the rule, notably the judiciary. They also constitute integrative tools of the system as they fill actual or potential legal gaps.
- Reference Works
In spite of what many authors of standard manuals of international rule have stated in introduction to their own theories, there is a surprising dearth of literature, given the importance and difficulty of the topic—and compared to the literature dedicated to treaty and custom law. Also, much of the literature generally addresses the general principles in an encompassing manner, dealing with all the aspects of the topic, be they its history, its meaning, its illustrations, and so forth. Given these two specific features, much of this literature can therefore be careful referential. Another exciting feature lies in the fact that this general literature is quite time-bound, with clear waves of works having been published at certain periods of time, such as during the years following the entrance into force of the Permanent Court of International Justice (PCIJ) and International Court of Justice (ICJ) Statute, or during the 1960s. Other recent works have also been written on the topic, yet without diminishing the intellectual aura those earlier workings still possess.
- Historical and Classical Pieces
These works of reference are fairly self-referential and generally build onto one another. Usually quite dated, they are thorough works of deep rigor and thinker subtlety; they also give for exhaustive bibliographies and case law references on the topic and on connected fields. They too constitute involuntary witnesses to a certain way of approaching international law and its historical progress. The workings referenced below are classified according to importance in terms of thoroughness and up-to-date knowledge. Pellet 1974 has contributed the mainly (and most recently) to the theory of the domain. Kolb 1999 (in French) on the rule of good faith provides exhaustive multilingual bibliographies and a true humanities perspective. Thus far, Cheng 2006 is the most current Western-oriented sum of knowledge in English on the topic after Lauterpacht 1927, which is usually characterized as the primary fundamental reference on the topic in the history of the field. Schwarzenberger 1955 is also still a usual reference, providing a perspective based on realism or power. The conciseness of Anzilotti 1999 on the subject did not preclude its fame. Herczegh 1969 is a short but dense contribution to the topic and abides for the mainly part to the so-called socialist legal theories of its time.