In response to a post (by Daniel Hoffman I think) about the treatment of plural marriage in a novel,
*** With apologies to those misguided list members who hate science fiction ***
At least one of Robert Heinlein's sci fi novels (The Moon is a Harsh Mistress, I think) includes a plural marriage concept that he called a "line marriage," in which new members are added from time to time, and old members are removed by death or divorce (based on a majority vote or perhaps based on the view of the senior partners, so to speak, but I don't remember it exactly). A line marriage could last for centuries.
A recent novel in David Weber's very popular Honor Harrington sci fi series has the title character (a woman who is a space naval officer) becoming the third member of a marriage, with the enthusiastic endorsement of the first wife, who had been paralyzed in an accident many years before and who admires Harrington. One of the cultures presented in that series of novels is a very religious one in which polygamy is normal (in part because the rather toxic environment of their planet disproportionately kills boys, with a resulting imbalance of men and women). Harrington's three person marriage is unusual in Harrington's home system's culture, but fully embraced by the other culture. The highly religious culture is presented with both positive and negative features, but the plural marriage element is presented mostly as a positive feature.
And then there are the novels by Iain M. Banks called the "Culture" series, in which a future libertarian/utopian star-spanning polity has essentially no limits on the forms of sexual and personal relationships (though that isn't the focus of the novels). Several of the novels in the Culture series (The Player of Games, Use of Weapons, Excession, and Look to Windward) are extraordinarily good. Banks also writes acclaimed "literary" novels that don't appeal to me (e.g., The Crow Road, and The Bridge), under the name Iain Banks (no middle initial).
Mark S. Scarberry
Pepperdine Univ. School of Law
Malibu, CA 90263