After a decade of citywide evangelistic campaigns through the 1950s, Latin America Mission and LAM director, Robert Kenneth Strachan, launched a new program for mass evangelism in 1959 — “Evangelism-in-Depth” (E/D) or, as it was known in South America, “Evangelismo a Fondo.” Building on LAM’s efforts to “Latin Americanize” mission work, the program grew from Strachan’s central principle that “the growth of any movement is in direct proportion to the success of that movement in mobilizing its total membership in the constant propagation of belief” (E/D Manual, CN 236, Folder 138-7).

E/D shifted the focus of evangelism from presenting a single professional evangelist in a one-time event to a countrywide, congregation and laity-based, year-long effort. Proposing “a lasting revolution in missionary strategy,” the E/D program sought to impart “an increased vision and a renewed conviction” to individual Christians, local churches, and national leaders “that the total evangelization of their community in their generation is a distinct possibility and their definite responsibility” (Folder 138-7).

While designed to be adapted to different regional contexts, the core of the E/D program consisted of organized prayer, training for lay Christians, preparation for counselors, follow-up with new Christians, widespread publicity, door-to-door visitation, local and regional evangelistic meetings, regional and national parades, radio and television programs, and widespread Bible and tract distribution. The program flourished on a broad scale in fourteen Latin American countries until 1971, continuing afterwards in Mexico.