Robert A. Heinlein consistently tackled social themes through the framework of his speculative fiction in such a way as to force to reader to confront his own opinions on the subject at hand. Though Heinlein’s work is generally considered to be “hard” sci-fi instead of space opera, the author seldom delved into the fundamentals of the science or problem solving behind the technology of his stories. Instead, Heinlein tended to focus on the evolution of society, the individual’s role within society, and the responsibility of individuals towards their society. His protagonists are nearly always adventurers, philosophers, or engineers of some sort instead of natural or mathematical scientists of the kind favored by Asimov.