Leonard died in 2013. If you read one thing by him, it’s this.

https://www.writingclasses.com/toolbox/tips-masters/elmore-leonard-10-rules-for-good-writing

His novels generally stick to the rules and are quick, short, entertaining reads that are super heavy on dialogue, which makes his work ideal for film adaptations (over 20 at last count on his Wiki, plus one TV series), so it’s not a huge investment of your time if you give one a try. I’m not a fan of his ’50s to early ’70s Westerns and it seems that most people agree that he only got his current reputation when he switched over to crime novels in the mid ’70s. Like I said, you can pick up most any of those at random from that era until the ’90s and know what to expect - he’s really consistent but some are better than others. You could start with those two I mentioned, or Get Shorty ( also a good film starring a pre-Sopranos James Gandolfini). Unknown Man #89, Cat Chaser, Out of Sight (not a good movie), La Brava, Split Images, Mr. Paradise - all solid from what I remember. “Never underestimate the stupidity of criminals,” is one his best quotes, and that’s one of the things I like about his plots. His protagonists aren’t diabolical masterminds, just dumb fuckups, and the score always goes wrong because someone makes some all too believably human idiot fuck up (remember De Niro shooting Bridget Fonda?). The main attraction of his style is the dialogue, of which he’s acknowledged along with David Mamet as one of the masters. He’s certainly better than the likes of James Ellroy, whose prose too often reads like he can barely mangle a mixed metaphor together.