A blog post from the lovely Dorte asking 'What is noir?' (a question to which it appears there is no definitive answer) leads me to this not altogether serious route from noir to cosy.
Noir fiction has our protagonist spiralling down into the pit of despair, thrown there by a mocking Fate, who then stands at the edge of the pit shovelling dirt onto the head of the protagonist until he is half-buried. Fate then throws the shovel down into the pit and the hapless protag reaches out for that glimmer of hope, only for it to whack him on the head and kill him. Noir for me ends with the characters going to prison/becoming alcoholics/ betraying each other and their own morals (if they had any to start with) - mostly a one book deal (after all, who'd want to put the poor sucker through all that again?)
Add a wisecracking sidekick, a couple of shoot-outs and the love of a good woman for our PI who decides he's going to kick the booze, and you have a hardboiled tale.
Add a nasty serial killer, a morgue, some sharp knives and a know-it-all woman with a degree in pathology, who just happens to be a cordon-bleu chef and you have a forensic thriller.
Give your serial killer a quirk and have him choose victims who are blue-eyed women with one arm who he drowns in a vat of hot chocolate while narrating The Rime of The Ancient Mariner. He then ties her to the bed and draws a picture of a squirrel on the wall and scatters rose petals around the bedroom floor, because he was burned by a scalding mug of hot chocolate when he was a baby, force-fed to him by his mother Rose, a Women's Royal Navy Sailor, who lost an arm in a bizarre accident involving a rabid squirrel. Add in a few italicised passages from the viewpoint of the killer and you have a psychological thriller.
Include quotes from an obscure Turkish poet left at the scene of the crime (the poem, not the poet), have the killer be a master chess-player and chuck in a discourse on philosophy every six pages, and you have a literary mystery.
Throw a lawyer into the mix who uses his courtroom skills to unveil the bad guy, despite the fact that his extra-curricular investigations puts his own life in danger, and you have a legal thriller.
Give your lawyer an acquaintance who's a cop with a passion for justice at the expense of his home life, who's been divorced six times, is driven by the job and who relaxes with a glass of beer and some jazz music on the stereo at the end of a case and you have the loner cop book.
Give him some mates, a few jokes, a couple of attractive female colleagues, an annoying senior officer, too much paperwork and some inter-departmental squabbling and you have a police procedural.
Introduce your newly optimistic and upbeat policeman to a nice widow with a penchant for sticking her nose in where it's not wanted, and who always seems to be tripping over dead bodies and you've got an amateur-sleuth mystery.
Give Ms Nosy a clever, mystery-solving iguana as a pet, a hobby knitting bird tables out of left-over wool, then throw in a recipe every couple of chapters and you have a cosy.
Make the iguana talk, and give him the starring role, or give the heroine the ghost of a dead relative to contend with and you have a paranormal crossover mystery.
Transport the whole shooting match back to 1665 and dress them in pantaloons and bustles and have them declaim "Gadzooks" and "Oddsbodkins" every now and again and you have a historical mystery. Well, you might have to lose the iguana...
So, dear Reader, what is your favourite sub-genre and why?