After 41 years in the wilderness, it seems that Bob Clark's seminal Toronto-shot horror film Black Christmas is finally getting the respect it's due.

Released with little fanfare into grindhouses and drive-ins back in 1974, Black Christmas arrives this week in a glorious 41st Anniversary "Season's Grievings" Bluray collector's edition, with a new sense of pride that its rightful place among titans of the horror genre has been certified.

John Carpenter's admittedly awesome Halloween (1978) usually gets all the props for being the brainy harbinger of the 1980s slasher craze (point-of-view killer, minimalist off-kilter soundtrack, an emphasis on tension over gore, etc.) but you will likely find all of that was done first in Black Christmas, four years earlier than Halloween (and here in Toronto!).

For anyone who has not already seen the film - be warned. Spoilers within!

Here are the 10 reasons why you need to (re)watch Toronto's ultimate horror movie.

FESTIVE FEAR
While many horror films have since been set during the Christmas season and made lazy use of its iconography, Black Christmas plays it intelligently. Anyone who's lived in residence at university knows that come the holidays, people begin to peel away quickly and quietly. It's just that kind of silent mass exodus that proves perfect cover for the nocturnal activities of a maniac killer.

LURID LOCALITY
Of course everyone in Toronto will immediately recognize the wintery University of Toronto scenery, but other locations are more subtle: the Police station (Main Street & Swanwick Avenue) also doubled as the Police station in Class of 1984, another under-appreciated cult Toronto film.

ORIGINAL URBAN LEGEND
The urban legend of a babysitter getting disturbing phone calls from inside the home she is occupying has terrified kids for decades, and appeared as a gimmick in many films (Scream, When A Stranger Calls, Urban Legend), but it was Black Christmas that used the trope first.

SPOOKY PHONE CALLS
The blood-curdling voice, cadence and language of the harassing calls made to the Sorority girls remains unmatched for terror in any horror film since. According to actor Nick Mancuso, he stood on his head while performing the dialogue to make it sound even more bizarre. Director Bob Clark (who also provided voices) egged him on to use the foulest of foul language.

CHILLING COLD
Like a few other Toronto-set horror films, specifically two from David Cronenberg - The Brood and Crash - Black Christmas manages to capture perfectly the ice cold ambience present in the city from November through March. The dead cold atmosphere only heightens a sense of impending doom.

DOUG MCGRATH
Playing a hapless desk cop, Doug McGrath manages to squeeze decent laughs and memorable personality out of a minor character. McGrath is a rare Cancon legends who appeared in countless films and TV shows - his vast filmography ranges from Goin' Down the Road to working with Clint Eastwood and Steven Spielberg, episodes of The Incredible Hulk, Sidestreet, Baretta and Dallas.

VARIED VULGARITY
Director Bob Clark had a legendary sense of humour, and a transgressive punk streak too. Black Christmas features many vulgar moments, from imagery on the girls bedroom walls to the shocking aural bombast of the C-word (still mostly forbidden in films circa 2015 - can you imagine hearing it in 1974?!), but it all helps nicely establish the very real life world being terrorized by the killer.

SINISTER SOUNDTRACK
Composer Carl Zittrer (who also scored Bob Clark's other famous Christmas movie, A Christmas Story) went minimal for maximum effect. His sonic assault contains more violence than you ever see on screen, and he manages to make a piano sound like a chainsaw -- no small feat.

MARGOT KIDDER
The whole cast of Black Christmas is uniformly excellent, but there's something about Kidder's 50 swilling, chain-smoking, foul-mouthed bully that leaves you shell-shocked. She's the ranting drunken aunt who doesn't know when it's time to zip it and leave the table, but played by future Lois Lane. It's a brilliant piece of casting.

THAT ENDING
The ending of Black Christmas remains the key to its sly genius. Perhaps we are so accustomed to movies over-explaining everything to the point of convolution that having everything left hanging and unexplained makes it extra unnerving. Also, the fact there was no sequel, or trashy direct-to-video franchise cranked out every year like its '80s offspring kept the story clean and unsullied

The 2006 remake, which was, of course, a burnt turkey, doesn't count.

In addition to the "Season's Grievings" Bluray collector's edition out now, Black Christmas is also screening Tuesday, December 15 at 9:00 PM at TIFF Bell Lightbox‎ and Saturday, December 19 at 7:00 PM at the Royal Cinema.

Black Christmas: Seasons Grievings artwork by "Ghoulish" Gary Pullin

Ed Conroy's Retrontario plumbs the seedy depths of Toronto flea markets, flooded basements, thrift shops and garage sales, mining old VHS and Betamax tapes that less than often contain incredible moments of history that were accidentally recorded but somehow survived the ravages of time. You can find more amazing stories and discoveries at www.retrontario.com.