If you look at an edition of the Doctrine and Covenants published prior to 1981, you would likely be very confused by the use of code names and code words. For example, Oliver Cowdery was called “Olihah” and Martin Harris? “Mehemson.”
According to an article published by the Church History Department, this was done “to avoid providing evidence for lawsuits against Church members.” The code names were replaced with actual names in the 1981 edition.
An article from the BYU Scholars Archive, states that the use of code names came on the heels of growing hostility toward the Church and as a result, “the decision was made to conceal the true identities of various early leaders, particularly those responsible for the economic matters of the Church. Since there were numerous problems connected with the early attempts to establish the law of consecration and stewardship; especially as it related to property holdings, it was nature to hide the identity of those assigned specific temporal duties.”
The Church History Department’s article, “Ask Us: Top Five Reference Questions about Doctrine and Covenants Publishing”, also includes information about sections that were included or excluded dependent on the specific edition of the Doctrine and Covenants. Learn more about how the Doctrine and Covenants has changed over time here.