Missionary work is one of the most important tasks undertaken by The Church of Jesus Christ of Latter-day Saints. Spreading the gospel is at the heart of the Savior's message to his apostles shortly before his ascension into heaven, "Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost," (Matt. 28:19). Full time missionaries of the Church are charged with teaching Christ's message. The questions of what to teach and how to teach it have led to four sets of formal missionary discussions published by the Church beginning in 1952 and continuing on to 1961, 1973 and 1986. This thesis will document the timeline of decisions that lead to the creation of the missionary manual Preach My Gospel introduced in 2004 which contains the fifth set of missionary lessons published by the Church.