Final answer:
Gabriel García Márquez was the key figure of what would become Mexican literature, a part of the Latin American 'boom' literary movement, and known for incorporating magical realism in his work.
Step-by-step explanation:
The key figure of what later became Mexican literature was Gabriel García Márquez. He was a part of the Latin American 'boom' literary movement, which also included writers like Mario Vargas Llosa, Julio Cortázar, and Carlos Fuentes. These writers incorporated aspects of magical realism into their work, which later influenced other authors like Isabel Allende and Salman Rushdie.