 After authoring two volumes of poetry (an additional early volume had appeared as a private edition), Susman went on to produce her first monograph, Das Wesen der modernen deutschen Lyrik (The Character of Modern German Poetry, 1910), which introduced the concept of the “lyrical I” as the key feature in modern poetry. Her first philosophical book, Vom Sinn der Liebe (Of the Meaning of Love, 1912), is an engaging study of sex, gender, and love whose approach to difference and alterity continues to command attention. The publication of the book led to a lasting friendship with Gustav Landauer, who wrote an enthusiastic review and whose political ideas Susman shared.