After detailing the laws of the suspected adulteress the Mishna moves to masechet Gittin. While the law of the Sotah is no longer applicable the laws of gittin are unfortunately very much so.
 
The masechet begins with the law that an agent who brings a getfrom medinat hayam, across the sea, must say “before me it was written and before me it was signed”. Right from the beginning we encounter the theme of distance reflecting the broken relationship of husband and wife. They are living “across the sea” from each other - both physically and emotionally. And instead of coming himself to divorce his wife, the soon to be ex-husband sends an agent to represent him. 
 
As the Mishna is a legal code[1] cases are brought in order to highlight legal principles. Those principles are often best illustrated through the use of more extreme examples. Nonetheless the choice of cases to discuss are always instructive. When the second chapter of the “sister” masechet of Gittin, Kiddushin, begins “a man may betroth his wife himself or through an agent” (Kiddushin 41a), the Gemara is quick to point out that mitzva bo yoter mebeshlochu,mitzvoth are greater when performed oneself rather than through an agent. Notably no such provision is stated by a get. It would be almost sacrilegious to claim giving a get is a mitzvah that one should strive to do oneself [2]. Rather it is what we call a matir, an action necessary in order to allow another action. The get allows and is the pre-condition to allowing the woman to remarry.  
 
Historians note that this notion of “distance” was one of the key factors leading to Rabbeinu Gershom’s ban of polygamy. Jewish businessmen would quite understandably often travel on very long trips leaving their families behind. These men were wont to marry another woman on these travels. One can imagine the impact such would have on a family and thus Rabbeinu Gershom banned, under pain of excommunication, polygamy despite it being allowed (though clearly discouraged) by the Torah. 
 
Much of masechet Gittin deals with the technical laws of writing and delivering a get: that it must be written lishma, for the specific divorcing couple, when it must be written (in the daytime), by whom, and what precise language must be included and excluded. Besides using agents it was apparently common for a man to leave a get in the property of his wife without actually giving it to her directly. Not surprisingly the proper method for cancelling an agency agreement is discussed. Not only by marriage do people get cold feet. 
 
It is this later issue that leads of a discussion off a topic of great interest to many, namely the annulment of marriage. The Gemara discusses how under certain circumstances the rabbis annulled marriages rather than allow the improper cancellation of an agency agreement. Such would obtain when one cancels the agency agreement without the wife’s knowledge potentially leading to a situation where a woman receives, unbeknownst to her, a get that has been cancelled and subsequently marries on that basis. 
 
Only in the very last Mishna of the masechet do we encounter a debate as to under which conditions one may or even should divorce his wife. From a legal perspective this of peripheral interest and has no bearing on how we execute a bill of divorce.
 
As a beautiful balance to the discord of divorce, masechet Gittin has two complete chapters (out of nine in total) discussing rabbinic laws instituted mifnei tikkun olam, for the betterment of the world and mifnei darchei shalom, to promote harmonious relations amongst people. The former include the institution of pruzbul, a decree forbidding the payment of excessive ransom to redeem hostages and the requirement to free a ‘half slave’ so that he may marry. The latter include the obligation to give the kohen the first aliyah, to lend one’s utensils to others even if they are ignorant of much of Jewish law and to allow the non-Jewish poor to enter your field to gather leket, shichecha and peah, the tithes the farmer must leave for the less fortunate. If only husband and wife had learned to practice darchei shalom
 
Being created in the image of G-d, our relations with others reflect our relationship with G-d. And that relationship is depicted as one between bride and groom with the wedding taking place at Sinai. If we get angry with those created in G-d’s image we are at the same time displaying anger towards G-d. When husband and wife must separate we are at the same time separating ourselves from G-d. No wonder the altar cries when a couple divorces (Gittin 90b). 
 
It is thus keeping with the theme of the masechet that the stories of the destruction of Temple and the subsequent exile are detailed in masechet Gittin. If husband and wife can go from love to separation is it any wonder Kamtza and Bar-Kamtza are not on speaking terms?Having a couple divorce is sad enough but when G-d divorces His people it is a national tragedy. Yet G-d is always ready to give the marriage a second chance. It is by walking in darchei shalom, the paths of peace between Jews, that the remarriage of G-d and His people can be completed.
 
[1] This is in contradistinction to the Gemara which is not a code at all. Even its legal discussions, which themselves form only part of the Gemara, are much more discussions of legal process than a code itself. More often than not the Gemara quotes a variety of opinions without reaching a conclusion.  
 
[2] We must distinguish between a technical mitzva and a mitzva which one should strive to do. Many of the 613 mitzvoth involve activities it is best to avoid, a get being just one example. On the other hand there are many activities we should, perhaps must, strive to do which are not part of the 613 mitzvoth. One possible fascinating example of the latter is the “mitzvah” of living in Israel which at least according to the Rambam is not one of the 613 mitzvoth. Perhaps for this reason our Talmudic sages did not concern themselves with a listing of mitzvoth - the first compendium of the 613 mitzvot appears only in the 8th century. We are to strive to do that which is positive and avoid that which is negative even if such do not exactly conform to the technical definition of mitzvoth.