Does the series have a defining, iconic location? Like Arkham in Lovecraft or Three Pines in Louise Penny? If so, starting at the beginning lets you experience the author discovering that place alongside you, which is a special kind of magic.
For a blend of personal and historical mystery, Philip Kerr's Bernie Gunther series is monumental. The ongoing plot is the mystery of surviving, morally intact, through the entirety of Nazi Germany and the Cold War. Each book is a slice of history where Bernie is trying to solve a crime while navigating the greatest crime of the century.
The overarching mystery is whether humanity, or one man's decency, can persist in such a system. It's a philosophical and historical mystery executed through a hard-boiled detective format. The strength lies in its unbearable moral weight and historical authenticity.
Technology's role in crime fiction has evolved entirely due to the times, but influential series show how to integrate it without killing suspense. Early on, the lack of cell phones or DNA analysis defined plots. Now, series like Michael Connelly's or even techno-thrillers have to grapple with digital footprints, hacking, and surveillance. The influence of the best series is in making the technology a integral part of the puzzle, not a magic wand. It creates new types of clues and new vulnerabilities, forcing detectives (and writers) to be savvy about both the capabilities and limitations of modern tech, ensuring the genre stays relevant to contemporary life.
For pure puzzle construction, you can't beat Ellery Queen (both the character and the writing duo). The early 'Golden Age' novels often featured the 'Challenge to the Reader', a direct address that all clues have been presented. They were games, and brilliantly constructed ones. 'The Greek Coffin Mystery' or 'Cat of Many Tails' are incredibly complex and fair-play. They represent the cerebral, plot-driven mystery at its most extreme. The later novels shifted to more psychological and procedural stuff, but the early works are monuments to the pure puzzle.
I judge a crime series by how well book one works. If the author didn’t stick the landing on their first attempt with these characters, why should I trust them to improve? I always start with book one. It’s the foundation. If it’s shaky, I move on. There are too many incredible series out there to waste time hoping it gets good later. A strong debut is a promise.
I find myself drawn to crime series that are about more than the crime. Something like 'The No. 1 Ladies' Detective Agency' by Alexander McCall Smith. It's gentle, philosophical, and set in Botswana. Precious Ramotswe solves small, human-scale mysteries with wisdom and kindness. It's the antidote to the grim, violent Nordic noir. The crimes are often matters of the heart or minor deceptions. It's a reminder that justice and resolution come in many forms. If you want something uplifting, warm, and deeply human to start with, this is a beautiful, unique corner of the genre.