Space opera is the most common, and least respected, form of science fiction. Its popularity in magazines of the 1920s and 1930s helped establish science fiction as a genre, and it continues to find appreciative readers, even while scorned by learned commentators. To many, space opera is synonymous with sf, and to this day, average citizens asked to define sf might respond, 'You know, the Star Trek, Star Wars stuff', which is to say, space opera. Still, although chastised for lacking merit and damaging the reputation of sf, space opera has endured, evolved and grown, so that sophisticated writers and scholars increasingly look to the form with bemused affection, or even genuine admiration.

Despite signs of changing attitudes, space opera has garnered little critical attention; only a few scholars have attempted anything resembling a rigorous definition. Necessarily, anyone discussing the nature, parameters and history of space opera at length breaks new ground.