Heinlein objected to Zell's lumping him with other writers such as Ayn Rand and Robert Rimmer; Heinlein felt that those writers used their art for propaganda purposes, while he simply asked questions of the reader, expecting each reader to answer for him- or herself. He wrote to Zell in a letter: "... each reader gets something different out of the book because he himself supplies the answers. If I managed to shake him loose from some prejudice, preconception or unexamined assumption, that was all I intended to do."