The papers include letters from various prominent Cuban figures; among them Tomás Estrada Palma, Salvador Cisneros, Lola R. de Tió, Armando Menocal, Mario Menocal and others.  The materials also consist of newspaper clippings about sugar industry and some photographs.

The papers document activities of Eugenio Castillo who was a lawyer and a Consul of Cuba before 1959.  He was associated with the following places: Cuba, London, New York, Paris and Baltimore.  The materials include correspondence with prominent Cuban figures including José Raul Capablanca, who was a Cuban chess player and a world chess champion from 1921 to 1927, Luis Machado and others, as well as, PelDrak Cuba Copper Products Corporation data and photographs, invitations, clippings, official papers signed by a president of the Republic of Cuba and memorabilia.