Kill Your Darlings (1984) by Max Allan Collins - the third in a string of mysteries published in the 80s featuring Collins' protagonist Mallory, a Vietnam vet, ex-cop and now struggling mystery writer in small-town Iowa who keeps running into "situations".
In Chicago, Mallory has finally been able to attend a Bouchercon, the big annual mystery convection, named after noted critic
Anthony Boucher. Collins points out in a note that, yes, Bouchercon is real, but this version doesn’t exist. (Though coincidentally the real 1984 Bouchercon did end up being held in Chicago). He is just using it since it fits the plot perfectly. Mallory is there to meet with one of his heroes, Roscoe Kane. Once a bestselling author of hardboiled crime fiction, especially his novels and stories featuring P.I. Gat Garson, he's fallen out of favor. In recent decades, his only newer work was published overseas. He claims to have been blacklisted by US publishers after suing the publisher of Gat Garson for royalties he claimed to have been cheated out of and the stink he raised was considerable.
Mallory befriended his idol years ago and despite the man's tendency to drunken ranting, is excited for him because after years of no critical recognition, Kane is about to be surprised with a Lifetime Achievement Award from the Private Eye Writers of America (a real organization, borrowed by Collins). So it's an unpleasant surprise when Kane is found drowned in his bathtub, apparently having sunk in while soused.
Mallory is certain it’s foul play, but the local police don’t buy it, so he’s determined to find the culprit. All of this takes place during the four-day convention where it’s going to be announced that the specialty publisher Mystery House (run by a character with whom Mallory has a...history) is going to be releasing a recently discovered unpublished Dashiell Hammett manuscript for a novel featuring his character
The Continental Op. Meanwhile, Mallory navigates the con while trying to run an investigation on the sly and hanging out with the attractive lass who is editor-in-chief for a magazine devoted to hard-boiled fiction.
It’s a fun mystery all around, keeping the reader guessing up to the reveal. And Mallory is such a likable figure, and proof that a mystery/crime fiction protagonist can be "tough but sensitive" without being a total wiener.