Social conduct literature consists on published documents aiming to somewhat control the population by consistently pointing out morality and how to live a virtuous life. The importance of this type of literature is more historical than social, when we look in a broader perspective. This is because these publishings show how society has changed throughout time, and how people have evolved with it. Moreover, social conduct literature enables the modern reader to go back in time and probably be shocked to find out what once was considered "acceptable" or "unacceptable" behavior, and the reasons why they were considered so.
This type of literature first came out during the Middle Ages and the Renaissance and, as it is known, only men were permitted to author work during that time. Once the printing press was created and put to use, the books became even more predominant on their own accord and were printed consistently.
During the Victorian times the social conduct literature books were of essence. You have, for example, Mrs. Beeton writing books on advice and "how to's" for a diversity of social situations. Religious, virtuous and somewhat prudish literature is also considered social conduct literature.
Even during the 20th century we have a number of etiquette publications and social concern magazines that also aim to tell readers about maintaining a style and propriety in conduct. To some people this may sound snobbish, but in reality there should be a baseline that can establish a specific set of behaviors that can differentiate people who stick to traditional norms from those who do not. Personally, I advocate modern social literature and I even collect antique books on social conduct from the 19th century. There is a wealth of information one can take from those amazing books.