His publications center largely on issues of modernism and postmodernism in twentieth-century peninsular poetry and include La poética de la generación del 27 y las revistas literarias: De la vanguardia al compromiso, Modernism and its Margins: Reinscribing Cultural Modernity from Spain and Latin America, Jorge Guillén: The Poetry and the Poet, and the edition of the Obra poética de Julio Vélez. Geist's other main field of research concerns art and literature of the Spanish Civil War. He published a photoessay on Seattle-area Lincoln Brigade veterans, coauthored with the Spanish photojournalist José Moreno: Passing the Torch: The Abraham Lincoln Brigade and its Legacy of Hope / Otra cara de América: Los brigadistas y su legado de esperanza. He has also curated a traveling exhibit of children's drawings from the Spanish Civil War, which toured the country for two years. The accompanying book, They Still Draw Pictures: Children's Art in Wartime from the Spanish Civil War to Kosovo, was published in 2002. Geist is Vice Chair of the Abraham Lincoln Brigade Archives and has been a journeyman carpenter for 30 years. In addition to modern Spanish literature, he also teaches Spanish cinema.