Seder Nashim—The Order of Women
An entire section of the Mishnah and Talmud is devoted to laws governing the relationship between men and women. Because those studying these laws were men, the order is appropriately named after the other party in the relationship. It is a relatively short Order, with only seven tractates—but, on the other hand, it is also the only Order that has both Jerusalem and Babylonian Talmuds for every tractate.
Marriage, Both Mandatory and Optional
Yevamos: Levirate Marriage. In Deuteronomy 25:5–10, the Torah commands that if a married man dies without children, his brother should marry the widow in order to continue his brother's name. This marriage is called yibum. If no brother wishes to do this, then the widow and one brother perform a ceremony called chalitzah to free them of the obligation.
Kesubos: Marriage Contracts. The Torah provides a model for the support of a wife, widow, and/or ex-wife that is thousands of years old. In the Kesubah, the prenuptial contract, the husband-to-be promises financial and other support to his bride during their marriage, as well as a substantial payment afterward. The Kesubah takes precedence over the children's inheritance—even those from another marriage—and most other debts that the departed might have had.
Vows and Oaths
Nedarim: Vows. This tractate discusses vows and oaths that a person can make, as well as how they can be annulled. While married, the Torah was concerned that a wife could make a vow that would bother her husband or otherwise disrupt the marriage, and permitted the husband to annul the vow immediately. According to Maimonides, this is why tractate Nedarim follows Kesubos. The husband has no such escape route—if his wife objects, he'll need to ask a Rabbi about annulment of the vow.
Nazir: the Nazirite Vow. A vow of Nezirus is a unique variety of oath, during which the Nazir could not cut his or her hair or drink wine. The husband could nullify this vow as well, another reason for this tractate to follow Nedarim.
Divorce and Betrothal
Gittin: Divorce. Taking a middle road between the complete rejection of divorce by some other religious viewpoints and the casual attitude toward divorce in Western society, the Torah and Talmud teach that a successful marriage is a goal to be achieved. If, on the other hand, the marriage does not succeed, then the couple are not stigmatized, but rather given extraordinary support. When a marriage fails, the husband gives the wife a document called a Get, thus entitling her to receive her Kesubah and to marry another.
Sotah: The Suspected Adulteress. Let's say a husband saw his wife frequently socializing with another man, and they even secluded themselves together in a home or office. The husband would be in a jealous rage, but there is a way to save the marriage if the wife did nothing wrong (if she admitted adultery, the marriage would end through divorce, which is why Sotah follows Gittin). She could go to the Temple, and drink water into which God's Holy Name had been erased. If she was innocent she would not be harmed, and the Torah would bless her as well. But if she compounded the sin of adultery by lying and causing God's Name to be destroyed, then she would be poisoned by the water. The Talmud says that God preferred to see His Name erased in order to preserve a marriage!
Kiddushin: Sanctification of Marriage. The first stage of getting married is an act of Kiddushin, betrothal, that sanctifies the marriage. In the Jewish wedding ceremony, this is why the first thing the groom does is give his wife the ring. According to Maimonides, Kiddushin was not included before Kesubos in order to keep Levirate and regular marriage together. Kiddushin was then left until after Gittin, divorce, because the verse says “She left his house, and she went and was married to another man” (Deut. 24:2).