Eiseley published works in a number of different genres including poetry, autobiography, history of science, biography, and nonfictional essays. In each piece of writing, he consistently used a poetic writing style. Eiseley's style mirrors what he called the concealed essay—a piece of writing that unites the personal dimension with more scientific thoughts. His writing was unique in that it could convey complex ideas about human origin and the relationship between humans and the natural world to a nonscientific audience. Robert G. Franke describes Eiseley's essays as theatrical and dramatic. He also notes the influence his father's hobby as an amateur Shakespearean actor may have had on Eiseley's writing, pointing out that his essays often contain dramatic elements that are usually present in plays.