Nezikin (Hebrew: נזיקין Neziqin, "Damages") or Seder Nezikin (סדר נזיקין, "The Order of Damages") is the fourth Order of the Mishna (also the Tosefta and Talmud). It deals largely with Jewish criminal and civil law and the Jewish court system.
Nezikin contains ten volumes (or "tractates"):
Originally, the first three volumes were counted as one single, very lengthy volume. Since it was the chief repository of "civil" law, it was simply called Massekhet Nezikin ("Tractate Damages").
The traditional reasoning for the order of the volumes of Nezikin is as follows: The Order begins with civil law (the first 3 tractates) because it is considered the cornerstone of righteousness within a Jewish state. Sanhedrin naturally follows, as it deals with criminal law. Next comes Makkot, as it is a continuation of Sanhedrin's subject matter in terms of criminal procedure. Then, Shevuot, which continues the general topic dealt with in Makkot of the false testimony. After outlining the main points of civil and criminal law, Eduyot follows to fit it all into a halakhic framework. After dealing with "damages" within a society, the next stage is Avodah Zarah placed after to highlight what is seen as behavior that inflicts damage on the universe. Avot is probably placed next to counteract the negativity of the laws of Avodah Zarah and to relate maxims of the Sages, an essential aspect of whose teaching was to counteract idolatry. Finally, Horayot brings the discussion from lofty heights to a humble note, highlighting the concept that even the Sages and battei din can err.
There is both a Babylonian and Jerusalem Talmud to each of the tractates except for Eduyot and Avot. This is probably because these two tractates aren't concerned with individual laws and therefore don't lend themselves to a Gemara style analysis.