The correspondence between Rivera and Pflueger before Art in Action began gives insight into Rivera's jovial character and alludes to the mysterious need for Rivera to leave Mexico in the Spring of 1940. The following four letters are courtesy of John Pflueger, Architect.

Undated letter from Rivera to Pflueger
In this letter, Rivera expresses his interest in Pflueger's "proposition."

Letter from Rivera to Pflueger on April 15, 1940
Rivera's acceptance of Pflueger's invitation to participate in the GGIE and paint a fresco.

Agreement on April 15, 1940
Signed by Rivera and Pflueger, this agreement outlines the scope of the mural project, including size, cost, and subject matter.

Undated letter (2) from Rivera to Pflueger
Rivera discloses his need to leave Mexico City as soon as possible.