S. A. Cosby (Shawn Cosby) is a 'Southern noir' mystery writer. He resides in a small town known as Gloucester, Virginia on the Atlantic coast. Cosby has published three crime novels: My Darkest Prayer, Blacktop Wasteland, and Razorblade Tears.

His latest novel, Razorblade Tears, debuted number 10 on the New York Times bestseller list. His previous novel, Blacktop Wasteland won a landslide of awards, including a Los Angeles Times Book Prize in 2020. It also was chosen as a 2020 New York Times Notable Book and charted at number 22 on that list. Additionally, Blacktop Wasteland is a 2021 Anthony Awards winner. The International Thriller Writers, an association spanning 49 countries, with a membership of 4,500 authors of the genre, named Cosby’s novel Blacktop Wasteland the Best Hard Cover Fiction Novel of 2021. Both novels have been optioned for films. Jerry Bruckheimer's company was among the group that won the film rights in an auction for Razorblade Tears. Razorblade Tears was also featured on Jimmy Fallon's Tonight Show for Fallon's 2021 Summer Reads Book Club. The book was one of six contenders for a Jimmy Fallon read.

When not writing, he is an avid hiker and chess player.