This is more or less the point of George Orwell’s “1984,” of course. As in Margaret Atwood’s “The Handmaid’s Tale” — which shares the crown with “1984” for most important speculative novel of the 20th century — the more omnipresent the role of the law, the less visible it becomes. We learn early on that in Oceania keeping a diary is “not illegal (nothing was illegal, since there are no longer any laws),” but if caught doing so one could be “reasonably certain that it would be punished by death, or at least by 25 years in a forced-labor camp.” To enforce these nonexistent laws, Orwell gave us the most famous imaginary cabinet departments of them all: the Ministries of Love, Peace, Plenty and Truth.

A very different alternate-universe England is that of Jasper Fforde’s Thursday Next series, starting in 2001 with “The Eyre Affair.” Fforde’s engineering of postwar Britain includes not just a lot of bizarro genetic science and winking literary jokes but also a comprehensively detailed investigational infrastructure. Thursday is an officer of SO-27, a special operative of the Literary Detective Division; her father, Colonel Next, was a member of the ChronoGuard, affiliated with the Office for Special Temporal Stability. In the follow-up series, officers investigate crimes in children’s literature under the auspices of the Nursery Crime division. (Obviously.)

Fforde’s speculative universe is playful; Orwell’s is cautionary and high-dystopian. The tonal range of the genre extends yet further, into worlds that feel not only intricate, but grounded — imaginary universes that are every bit as fanciful, but feel less so. For Everfair, the titular African nation of Nisi Shawl’s magisterial 2017 novel rewriting the history of the Belgian Congo, the author created an entire country and its institutions from scratch. Kingsley Amis likewise builds a complete legal language suited to the alternate England of “The Alteration” (1976), in which the Reformation never occurred — Martin Luther having reconciled himself to Catholicism and become Pope Germanian I — and laws are not laws at all, but “Acts of Convocation.”

Of course, suspension of disbelief is involved: These laws and statutes and cabinet departments never sound quite real. On the other hand, consider that the language of public life, of real life, often has a certain invented ring to it. Think of all the scraps of language that float into everyday consciousness from the public sphere: Sarbanes-Oxley. The Department of Homeland Security. How about the long-awaited Mueller report? Say it a few times and it starts to sound like make-believe. Little wonder that authors seize on the same sorts of phrasing so their make-believe worlds might feel less so.

Sometimes writers don’t even have to invent. I remember being astonished by the chutzpah of Michael Chabon’s premise for “The Yiddish Policemen’s Union” (2007): the endangered Jews of Europe being handed a scrap of Alaska instead of Palestine. And I remember my subsequent astonishment to discover that Chabon had stolen the idea from Franklin Delano Roosevelt’s secretary of the interior, Harold Ickes, who first proposed it in 1938.