From the front cover:
"Its prize space-colony had grown silent - and Earth wanted to know why."
Plot: When the beacon signal from Beta Hydri, a human "space colony" on Mars, goes dead for forty hours - indicating almost near-certain disaster - and a notorious author (Kit Carew) goes missing there as well, reporter Jeremy White is sent there to investigate what happened. Accompanying him is a motley crew with mixed, possibly dangerous motives: Liss Landis, a flirty fellow reporter; Abigail Crane, Carew's secret sister and head of the Triple-C Corporation, whose financial ties to Beta Hydri are complex; Fanny Allen, a promiscuous, petulant socialite and Carew's sugar mama; and Miguel Santana, a playboy with hidden talents - and possibly another identity.
Earthstrings reads like an high-spirited Swingin' Sixties science fiction parody - there's plenty of science fictionish-sounding devices, the characters wear different colored skin suits which highlight their curves (particularly the women's), there's a strong element of mystery and lots of twists, and the women act like "Bond girls," in the sense that they fall over themselves to get with the mission-focused, sometimes taciturn Jeremy White.
This is a fast blast, wildly entertaining pot boiler, one worth owning.
Earthstrings was packaged as a reverse-bound "Ace Double" novel, which means that if readers flip the book upside down and over, there was another science fiction novel, penned by another author, on the other side. (Considering that these books sold for 95 cents a pop, this seems like a great deal, even back in that less-expensive, Seventies economy.)
In this case, the flipside novel is Kenneth Bulmer's The Chariots of Ra.