A memorandum usually takes place in the epilogue of the first three Maze Runner books. Memorandums always have a date, a time when it was written, who it was from, who it is for, and what it is about. The Kill Order is the only one that does not have such letters, while The Fever Code has the most. These memorandums are usually written by the World Catastrophe Killzone Department. Memorandums usually explain what has happened (or as far as we know, will happen especially in later books).
The memorandum for the first book stated how well Group A's maze trials went.
The final one said that the cure was not created. It also said that it was infact, WICKED's government predecessors, the Post-Flares Coalition had released the Flare virus so as to control the world's population. However, the Flare caused an outbreak and it infected most of the world's people and turned them into Cranks. The remaining governments created the World In Catastrophe: Killzone Experiment Department. They tried to find a cure and when they had failed, they had those who were immune sent to a safe place. They had preserved the human thoughmany could believe that WICKED wanted the humans extinct. which is why they state "WICKED is good".