Court of Crows is a court drama originally published in 1961 in hardcover and then published at least twice in paperback by Popular Library, in 1963 and 1967. Although reviewed in the New York Times when released it is so unknown today as to not even be found on Goodreads.
From the back cover "A fascinating journey into the devious twistings of adultery, murder and betrayal among a decadent people..." and "...because she was an adulteress, she stood trial for murder...an impressively substantial novel..."
There are a fair number of copies available on the secondary market. Fourteen copies on Biblio, for example, as low as $5.99.
Information on Knowlton himself is harder to find. He was an officer in the Navy and an editor at the United Press. Born in 1914, he died young in 1968. His father was a well-known trial lawyer in Massachusetts.

Romance and Mystery are by far the two largest genres of fiction. Harlequin capitalized on this with their Intrigue series.
Romantic Suspense was first popularized in the 1950s and 1960s with the likes of Mary Stewart, Victoria Holt, and Phyllis Whitney. Harlequin launched Intrigue, with contemporary timelines and characters, in 1984. 
The Intrigue series, like other "harlequin" series, developed subseries within, usually based on a family (The McKenna Legacy), an organization (The Colby Agency) or a location (The Rose Tattoo). The subseries could be written by a single author, as our example today where all 12 volumes in The Rose Tattoo subseries were written by Kelsey Roberts, or multi-author, like the Colby Agency subseries.
Her Mother's Arms combines an adopted heroine looking for her biological mother, a sexy ex-CIA agent, and someone looking to kill the heroine for the truths she may uncover. As with most serial romances the story unrolls quickly and ends predictably but it is a fun ride. Intrigues run to about 250 pages, still well within a single evening's sitting.
Her Mother's Arms is a typical example of the genre and the series. It gets a 4.0 rating on Goodreads. Her Mother's Arms is available on Biblio for as little as $3.97.

On Throwback Thursday I will bring a brief re-introduction to a book out of print.
Last week it was a serial romance; this week I push back even further, to 1964 with a hard-boiled espionage thriller from Edward S. Aarons, Assignment Sulu Sea. This book was originally published in 1964 and went right to paperback. It was reprinted three more times, all by Fawcett - 1968, 1974, and 1981. It is the 20th book by Aarons featuring CIA agent Sam Durrell. It has a 3.54 star rating on Goodreads.
This novel, like the other 41 in the series, was set outside the U.S. and in the same temporal period as it was written (i.e. the 1960s). So the themes are the Cold War themes of the day. Aarons sold over 23 million books in the Durrell series, rivalling, at the time, Ian Fleming's James Bond novels in popularity. 
Assignment Sulu Sea is short, only 160 pages, so can be read in an evening. Durrell finds himself in a mystery with a missing submarine, friends in unexpected places, murder, and political intrigue in a Pacific island chain. It can be bought for as little as $5.63 on Biblio.

Let me start by saying that, although I own a Kindle, I still prefer the feel of a paper book in my hands. It is my plan to provide periodically a review of a book that is no longer in print but is available in the secondary market for a reasonable amount. 
Let me further inform you, before we get any further along, that I used to own a used book store with the largest collection of serial romance novels in New York, as far as I can tell.
Romance novels, at least since the early 1970s in the United States, have been massively successful and the primary success, until recently, in terms of actual titles and copies printed, was in the serial romance category, colloquially known by the name of the powerhouse publisher as “harlequins”. Each title typically had only a single print run and was released once, as part of a group of books, or “series” that were similar in format and level of eroticism and adventure.
By design then almost all serial romances are no longer in print and often were printed in relatively small numbers per title. One such title, from the Temptation series, is Alyssa Dean’s Manhunting in Miami. Dean wrote 6 novels for the series in all and Manhunting in Miami is probably her best. She got 4 stars from Romantic Times when the book came out and has an overall rating of 3.57 stars on Goodreads. Described as “lighthearted and humorous” it involves a professional woman who hires an investigator to find her husband candidates who will satisfy both herself and her upper-crust family.
Manhunting in Miami is available for as little as $4.75 from Biblio.