A tightly plotted series of short mystery novels has recently come to my attention. 

The protagonist, Connie Murphy, is a senior drug investigator with the U.S. Food and Drug Administration. Based, at least in part on the author's own experiences, Connie is dedicated to protecting public health and safety, but finds intrigue and danger in the course of what should be routine inspections.

Cheat to Win is the seventh installment of the Connie Murphy mysteries, though each is a standalone work and I would encourage you to jump right in!

Connie's pre-approval inspection at Triple A Labs was suddenly and unexpectedly cancelled. Days later, she discovers that their application has been completely deleted from the FDA files, and the FDA reviewer who was working on the application has disappeared. Connie must find out what is going on...

Cheat to Win is novella length (about 80 pages) and highly recommended. (Link to Amazon ebook). Click this link for all the Connie Murphy mysteries!

In 1982 Sue Grafton introduced private investigator Kinsey Milhone and the "alphabet" series was born. Grafton passed away in 2017 but she left us a gem of a series with these novels which finished using all of the letters but Z.
Grafton's father was a writer of detective fiction and Grafton's first attempts at novels were in that genre. However they did not enjoy commercial success and she turned to writing screenplays. Always fascinated with series whose titles were somehow related, like John D. McDonald's series of "color" novels, Grafton hit on the idea after reading Edward Gorey's Gashlycrumb Tinies.
Each of the books is told from Milhone's perspective and is reminiscent of the "hard-boiled" detective novel of the 1950's. Grafton described Milhone as "the person I might have been had I not married young and had children". Milhone is tough and single, though clearly heterosexual and complex.
The alphabet series is consistently rated at about 3.95 on Goodreads with some slight variation. A is for Alibi currently stands at a 3.82. The series is recommended for those who like their detective fiction told in first person and a little hard-boiled.
From the back:
"Laurence Fife was a slick divorce lawyer and slippery ladies' man. Until someone killed him. The jury believed that it was his pretty young wife, Nikki, so they sent her to prison for eight years. Now Nikki's out on parole and Kinsey Millhone's in for trouble. Nikki hires Kinsey to discover who really killed her husband. But the trail is eight years cold, and at the end is a chilling twist even Kinsey doesn't suspect--a second eight-year-old murder and a brand-new corpse." 
​A is for Alibi is available on Biblio for as little as $3.94, including shipping.

Better late than never. On this special Friday edition of Throwback Thursday...
Sherlock Holmes is possibly the most well-known fictional detective in the world. He is so famous that over 100 years from his introduction he has his own television show and the books retelling his many cases are still in print and in demand.
Homes made his debut in the short novel A Study in Scarlet in 1887. Eventually Doyle would publish 56 short stories and 4 novels featuring Holmes, the last 40 years after A Study in Scarlet. Doyle famously was annoyed by the success of Holmes, wanting to spend time on other writing projects. Doyle was a prolific writer and diverse. He wrote seven historical novels, nine other novels, multiple plays, and literally hundreds of short stories. He considered his historical novels his best work, though few could name them today.
A Study in Scarlet mixes many things, like all of the Holmes stories it is a complex tale. Narrated by the inimical Dr. Watson, it mixes love, religion (the Church of Jesus Christ of the Latter Day Saints, the Mormons, are a prominent part of the story), the American West, and industrial age England. It introduces the Baker Street Irregulars, essentially street urchins employed by Holmes to scout the environs. It brings forth Inspector Lestrade of Scotland Yard and, in the end, the recurring theme that the police get the credit while Holmes takes a back seat.
I first read the Holmes stories as a teenager and have a facsimile copy of the Strand stories on my book shelf. You could definitely read worse!
A Study in Scarlet is plentifully available in multiple editions starting at only $3.94 including shipping on Biblio.